What is this file? Paste the name and find out

The odd files that appear on your computer — .aae, .crdownload, .part, .dat, .tmp — each get a plain-English page here: what it is, whether it is safe to delete, and what opens it. The identifier below matches the extension in your browser; nothing is uploaded.

Popular file types

The ones people ask about most — the temporary, backup and auto-save files Windows and Office leave behind.

Common questions

Straight answers to the things people actually search for.

• Is it safe to delete .tmp files? — when Windows temp files are junk and when they are not.
• Is Thumbs.db a virus? — what the hidden thumbnail cache really is.
• How do I recover an unsaved Word document? — using the .asd AutoRecover file.
• Why is my Chrome download stuck as .crdownload? — finishing or removing a half-done download.
• Where does Word save AutoRecover (.asd) files? — the exact folder paths.
• .part vs .crdownload — what's the difference? — Firefox vs Chrome unfinished downloads.
• .tmp vs .temp — are they the same? — why both appear and which you can clear.
• How do I open or restore a .bak backup? — step by step for common programs.
• Where are temp files stored on Windows? — the locations to check and clean.
• What is a .swp file? — the Vim/Vi swap file, and how to recover unsaved edits from it.
• Is it safe to delete .dmp (memory dump) files? — when crash dumps are junk and when to keep them.
• What is a .partial file? — the half-finished download, and how to resume or remove it.

All file guides

• Are .bak Files Safe to Delete? (Backup Files) — A .bak file is a backup copy an app saves before changing the original. Once the current file is confirmed good, deleting the .bak is safe — but keep recent ones as a rollback.
• "Found a Swap File by the Name" in Vim — What It Means and How to Recover — Vim says 'Found a swap file by the name .filename.swp' on open. Here's what the warning means and exactly which key to press to recover your unsaved changes or delete the leftover .swp.
• Are .CHK Files Safe to Delete? (FOUND.000 Folder) — A .chk file in a FOUND.000 folder is a fragment CHKDSK recovered from a damaged disk. Once your real files are intact, deleting .chk files is safe and reclaims the space.
• Are .GID Files Safe to Delete? (Windows Help Index) — A .gid file is a hidden Windows Help search-index cache created by WinHelp. It is obsolete on modern Windows and safe to delete — Windows recreates it automatically if ever needed.
• What Is a .asv File? (Recover Your MATLAB Autosave) — A .asv file is the autosave backup MATLAB makes of your .m script. Here is how to open it, turn it back into working code, and recover work after a crash.
• What Is a .ldb File? (Access Lock File That Will Not Delete) — A .ldb file is the record-locking file older Microsoft Access versions create next to an .mdb database. Here is why it stays behind, if it is safe to delete, and how to clear a stuck one.
• What Is a .dwl / .dwl2 File? (AutoCAD Lock File You Can Delete) — A .dwl (and companion .dwl2) file is the lock AutoCAD creates while a drawing is open. Here is why it lingers after a crash, whether it is safe to delete, and how to clear a stuck one.
• What Is a .idlk File? (InDesign Lock File — Safe to Delete) — A .idlk file is the lock file Adobe InDesign creates while a document is open. Here is why it lingers after a crash, whether it is safe to delete, and how to clear a stuck one.
• Download Stuck at 100% But Not Finishing — How to Fix It — Your download says 100% but won't complete or open. Here's why browsers freeze at the end (it's the virus scan) and how to force the file to finish.
• Microsoft Edge Download Stuck or Not Finishing — How to Fix It — Edge download frozen at 100% or stuck halfway? Here's the fastest fix and why Edge stalls on the final SmartScreen check — with steps that actually resume it.
• Recover an Unsaved File in Sublime Text After a Crash — Sublime Text closed or crashed with unsaved tabs? Your text lives in Session.sublime_session. Here's where to find it and how to pull your work back out.
• Recover an Unsaved File in VS Code After Closing or a Crash — Closed VS Code with unsaved changes? Your text is still in the Backups folder. Here's exactly where to find it and how to restore it in one step.
• Is a .crdownload File Safe to Delete? (Unfinished Chrome Downloads) — A .crdownload file is a partly-downloaded file held by Chrome, Edge or Brave. It is safe to delete whenever you don't need to finish that download — here's when and how.
• .swp vs .swo — What's the Difference? (Vim Swap Files) — Both are Vim swap files, but .swo appears when a .swp already exists. Here's why Vim makes a second one and which to recover from.
• Recover an Unsaved nano File: What the .save File Is & How to Use It — nano crashed and left a .save file? Here's what nano's emergency .save file is, exactly how to recover your unsaved text from it, and why it's not a swap file.
• What Is a .laccdb File? (Access Lock File You Can Delete) — A .laccdb file is the lock file Microsoft Access creates while a database is open. Here is why it stays behind, whether it is safe to delete, and how to clear a stuck one.
• What Is a .~lock File? (LibreOffice Lock File) — A .~lock file is LibreOffice's lock file that marks a document as open. Here is why it appears, whether it's safe to delete, and how to fix a stale lock.
• Can't Delete a ~$ File or 'Locked for Editing'? (Office Owner File) — That tiny ~$ file next to your Word/Excel document is an Office owner (lock) file. Here's why 'locked for editing' appears and how to delete a stale ~$ file safely.
• What Is a File Ending in ~ (Tilde)? Editor Backup File — A filename ending in ~ (like notes.txt~) is an automatic backup made by text editors such as Emacs, gedit and nano. Here is what it holds, how to open it, and whether it is safe to delete.
• Recover an Unsaved Notepad++ File After a Crash — Notepad++ closed before you saved? Your text is almost always still in its backup folder. Here's the exact path and how to restore it.
• Vim: Swap File Already Exists — Recover, Edit, or Delete? — Vim warns 'Swap file ".file.swp" already exists!' — here's how to tell if a session is still running, recover unsaved edits with (R), and safely delete the stale swap.
• Convert .crdownload to MP4 — How to Play an Incomplete Video — You have a .crdownload file and want the video. Renaming to .mp4 only works if the download actually finished. Here's how to tell, and how to play a partial video.
• Firefox Download Stuck at 100% — How to Fix the .part File — Firefox shows a download at 100% but it never finishes and leaves a .part file. Here's why it stalls at the end and how to get the completed file.
• Vim E325: ATTENTION — Swap File Error Explained & Fixed — Vim stops with 'E325: ATTENTION, found a swap file already exists'. Here's exactly what it means, which prompt option to pick, and how to clear it for good.
• Chrome Download Stuck or Not Finishing — How to Fix It — A Chrome download frozen at 100% or stuck part-way? The usual cause is antivirus scanning or a stalled connection. Here's the fix order that actually works.
• How to Open a .crdownload File (and Play a Partial Download) — A .crdownload file is an unfinished Chrome download. Here's how to open or play what you've already got — and why finishing the download is almost always the real fix.
• Can't Delete a .crdownload File — How to Remove It — Windows or Mac won't let you delete a .crdownload file because Chrome still has it open. Here's how to cancel the download and remove the stuck partial file.
• Can't Delete a .part File — How to Remove It (Firefox) — A .part file won't delete because Firefox (or a download manager) still has it open. Here's how to cancel the download and remove the stuck partial file.
• How to Safely Delete a Vim .swp Swap File — The .swp warning won't stop and you don't need the unsaved changes. Here's how to delete a Vim swap file safely — and make sure nothing important is lost first.
• Found a Swap File by the Name — What to Do (Vim E325) — Vim says 'Found a swap file by the name ...' and offers (O)pen (R)ecover (D)elete (Q)uit. Here's what each option means and which to pick.
• How to Recover Unsaved Work After a Crash — Which File to Look For — App or PC crashed before you saved? Each program leaves a different recovery file. Here's which hidden file holds your unsaved work and how to open it.
• How to Resume an Interrupted Download (Chrome & Firefox) — Your download failed partway and left a .crdownload or .part file. Here's how to resume it in Chrome and Firefox instead of starting over.
• What Is a .SWN File? — A .swn file is Vim's third swap file, created when both .swp and .swo already exist. Here is what it means and how to recover or delete it.
• What Is a .SWO File? — A .swo file is Vim's second swap file, created when a .swp already exists. Here is why it appears and how to recover or safely delete it.
• What Is a .un~ File? (Vim Undo File) — A .un~ file is Vim's persistent undo history for a document. Here is what it stores, why it appears, and how to move or safely delete it.
• What Is a .BK File? — A .bk file is a backup copy an app made before changing the original. Here is what creates it, how to open it, and whether deleting it is safe.
• What Is a .BKP File? — A .bkp file is a backup an app or user made of important data. Here is what creates it, how to open it, and whether it is safe to delete.
• What Is a .ORIG File? — A .orig file is the original copy a tool kept before it patched or merged your file. Here is what creates it, how to use it, and whether to delete it.
• What Is a .!QB File? — A .!qb file is an incomplete download from qBittorrent. Here is what it means, how to finish it, and whether it is safe to delete.
• What Is a .SAV File? — A .sav file stores saved data — usually a game save or an app backup. Here is what makes it, how to open it, and whether deleting it loses progress.
• What Is a .CACHE File? — A .cache file stores data an app saved to load faster next time. Here is what uses it, how to open it, and whether deleting it is safe.
• What Is a .FILEPART File? — A .filepart file is an incomplete download. Here is how to finish it, open the finished file, and whether a leftover .filepart is safe to delete.
• What Is a .TEMP File? — A .temp file is a temporary file an app left behind while working. Here is what created it, how to open it, and whether it is safe to delete.
• What Is a .!UT File? — A .!ut file is an incomplete uTorrent/BitTorrent download. Here is how to finish it, when it becomes usable, and if a leftover .!ut is safe to delete.
• .asd vs .wbk — Word AutoRecover or Backup? — Both are Word safety files, but .asd is a temporary AutoRecover autosave and .wbk is a saved backup copy. Here is how to open each.
• .bak vs .old — Which Backup Should You Keep? — Both are backup copies, but .bak is made on purpose and .old is usually a renamed leftover. Here is how to tell them apart and which to restore.
• .crdownload vs .opdownload — What's the Difference? — Both are unfinished downloads. .crdownload is Chrome and Edge; .opdownload is Opera. Here is what each means and how to finish it.
• .part vs .crdownload — What's the Difference? — Both are unfinished downloads, but .part is Firefox and .crdownload is Chrome. Here is what each means and whether you can open one.
• .tmp vs .temp — Are They the Same File? — Both mark temporary data, but they are not identical. Here is who creates .tmp vs .temp files and whether either is safe to delete.
• Where Are .chk Files (FOUND.000) Stored? — Where chkdsk puts recovered .chk fragments — the hidden FOUND.000 folders — and what to do with them.
• Where Are .dmp Crash Dump Files Located on Windows? — The folders that hold Windows minidumps, the full memory dump, and per-app crash dumps.
• Where Are Temp Files Stored on Windows? (.tmp Location) — The exact folders where Windows keeps .tmp and temporary files, and how to open them in one step.
• Where Are Thumbs.db Files Stored? — Why Thumbs.db appears in your folders, where exactly it lives, and how to stop it being created.
• Where Does Word Save .asd AutoRecover Files? — The default folder Word uses for .asd AutoRecover files, and how to find the exact path on your PC.
• How to Recover Data from .CHK Files (FOUND.000) — CHKDSK left FILE0000.CHK files in a FOUND.000 folder. Here is how to identify and recover usable data from them.
• How to Recover an Excel Workbook from a .XLK Backup — A .xlk is Excel's backup workbook — your spreadsheet one save behind. Here is how to open and recover from it.
• How to Recover an Unsaved Word Document (.asd AutoRecover) — Word crashed and you lost your document? Here is exactly how to recover it from the .asd AutoRecover file, step by step, on Windows and Mac.
• How to Recover Unsaved Changes from a Vim .swp File — Vim left a .swp swap file after a crash. Here is how to recover your unsaved changes from it and clear the 'swap file already exists' warning.
• How to Restore a Word Document from a .WBK Backup — A .wbk is Word's 'Backup of' file — the previous saved version of your document. Here is how to open and restore it.
• How to Restore a File from a .BAK Backup — A .bak file is a backup an app saved before overwriting the original. Here is how to restore your data from it and open it in the right program.
• What Is an .ASD File? — An .asd file is Microsoft Word's AutoRecover save. Here is how to recover your document from it and where Word keeps them.
• What Is a .BAK File? — A .bak file is a backup copy an app made before changing the original. Here is how to open it, restore it, or safely delete it.
• What Is a .CHK File? — A .chk file is a fragment CHKDSK recovered from a damaged disk. Here is how to identify what it was and whether you can restore it.
• What Is a CRDOWNLOAD File? — A .crdownload file is a download Chrome hasn't finished yet. Here is how to complete it, resume it, or safely delete a stuck one.
• What Is a DAT File? — A .dat file is generic data — its format depends entirely on the program that made it. Here is how to figure out what yours is, including the winmail.dat email case.
• What Is a .DOWNLOAD File? — A .download file is a download Safari hasn't finished. Here is how to resume it, complete it, or safely delete one that is stuck.
• How to Remove .DS_Store Files from Git and Windows — A Mac keeps adding hidden .DS_Store files that clutter your Git repo, ZIP uploads and Windows folders. How to delete them all and stop them coming back.
• Can I Delete a .GID File? Safe Cleanup Guide — Found a hidden .gid file taking up space? It is a rebuildable Windows Help index. Here is whether it is safe to delete and how.
• What Is an .INI File? — An .ini file is a plain-text configuration file that stores program settings. Here is how to open and edit one, and what desktop.ini does.
• All My Files Turned Into .LNK Shortcuts? Remove the Shortcut Virus — Every file on a USB drive or folder became a .lnk shortcut and the originals seem gone — the classic shortcut-virus symptom. How to unhide your real files and clean the drive.
• Photos Disappeared From Android Gallery? It Is a .nomedia File — Photos vanished from Gallery but the files are still on your phone? A hidden .nomedia file is telling Android to skip that folder. Here is how to find and delete it.
• What Is a PART File? — A .part file is an incomplete download, usually from Firefox or a download manager. Here is how to complete it or safely delete a stuck one.
• What Is a .PARTIAL File? — A .partial file is a download your browser hasn't finished yet. Here is how to resume it, complete it, or safely delete a stuck one.
• What Is a .SWP File? — A .swp file is Vim's swap file for recovering unsaved edits. Here is how to recover your work and safely delete a leftover one.
• Can't Delete a Folder Because of Thumbs.db? Fix It Here — Thumbs.db locks folders with a file in use error and keeps reappearing on network shares and in Git. How to delete it safely and stop Windows from creating it again.
• What Is a .CRSWAP File? — A .crswap file is a temporary scratch file written by Chrome or ChromeOS during a save. Here is what it is and whether you can delete it.
• What Is a TMP File? — A .tmp file is a temporary scratch file left by a program. Here is what makes them, whether they are safe to delete, and how to clean them up.
• Is a .DAT File a Virus? Is It Safe to Delete? — A .dat file is usually harmless application data, not a virus — but because .dat is a generic container, it depends on which program made it. Here is how to tell if yours is safe to delete.
• Is desktop.ini a Virus? Is It Safe to Delete? — desktop.ini is a normal hidden Windows file that stores how a folder looks (icon, name). It is not a virus. Deleting it is safe but only resets the folder's custom appearance.
• Are .dmp Files Safe to Delete? (Memory Dumps) — A .dmp file is a memory dump saved after a crash for debugging. Once you no longer need to diagnose the crash, deleting .dmp files is safe and can free several gigabytes.
• Are .log Files Safe to Delete? — A .log file is a plain-text record of what a program did. Deleting old logs is safe and frees space, as long as the app is closed and you don't need the history for troubleshooting.
• Is Thumbs.db a Virus? Is It Safe to Delete? — Thumbs.db is a normal Windows file, not a virus. It caches folder thumbnails. Deleting it is safe — Windows just rebuilds it. Here is how to be sure and stop it coming back.
• Is It Safe to Delete .tmp Files? — .tmp files are temporary leftovers programs forgot to clean up. Deleting the ones not in use is safe and frees space. Here is how to remove them without breaking an open app.
• Chrome Download Stuck as .crdownload (Not Finishing) — Fix — A .crdownload file that never becomes the real download means Chrome stalled. Here are the exact steps to resume it, restart it, or clear a stuck one.
• Safari .download File Stuck (Not Finishing) on Mac — Fix — A .download file that never completes is a stalled Safari download on macOS. Here is how to resume it, restart it, or safely clear a stuck .download file.
• Opera .opdownload Stuck / Not Completing — Fix — An .opdownload file that never finishes means an Opera download stalled. Here is how to resume it, restart it, or safely clear a stuck .opdownload file.
• Firefox .part File Won't Finish Downloading — Fix — A .part file that never completes means Firefox stalled the download. Here is how to resume it, restart it, or safely remove a stuck .part file.
• .partial File Won't Finish Downloading (Edge/IE) — Fix — A .partial file that never completes is a stalled Microsoft Edge or Internet Explorer download. Here is how to resume it, restart it, or clear a stuck .partial file.
• What Is a .001 File? (split archive part) — A .001 file is the first piece of a large file that was split into numbered parts. Here is how to join them and open the result.
• Can I Delete .AAE Files? (iPhone Photo Edit Files Explained) — Each iPhone photo you copied to your PC came with a matching .aae file. It stores your edits, not the photo. Here's when it's safe to delete .aae files.
• Leftover .aria2 File? Resume or Delete a Stuck Download — A half-downloaded file left an .aria2 control file behind. Here is how to resume the download or safely delete the leftover.
• What Is a .DMP File? (Windows crash dump) — A .dmp file is a crash dump Windows writes when a program or the whole system fails. Here is what is inside and whether you can delete it.
• What Is a .LOG File? — A .log file is a plain-text record of what a program did. Here is how to open one and whether you can delete it.
• What Is a .OLD File? — A .old file is a renamed backup of an original file, kept before it was replaced. Here is how to restore it and whether to delete it.
• Opera Download Stuck as .OPDOWNLOAD? How to Finish or Delete It — An .opdownload file is an Opera download that never finished. Here's how to resume or complete it — or safely delete a stuck .opdownload.
• Can I Delete .PNF Files in C:\Windows\INF? (Safe Cleanup) — Seeing hundreds of .pnf files in C:\Windows\INF and wondering if you can clear them? Here is what a precompiled INF does and whether deleting it breaks drivers.
• Recover a Word Document From a .wbk Backup File — Word saved a .wbk backup next to your document. Here's how to open it and get your lost text back.
• What Is an .XLK File? (Excel backup) — An .xlk file is a backup copy Excel made of your spreadsheet. Here is how to open it and get your data back.