What Is an .ARIA2 File?
You have a file ending in .aria2 sitting next to a half-downloaded file. It is a resume record for the aria2 downloader. Here is how to use it or clear it.
What an .aria2 file is
An .aria2 file is a small control file created by the aria2 download utility (used on its own and by front-ends like Motrix and some managers). It records which pieces of a download have already arrived so aria2 can resume instead of starting over. It sits beside the partial file with the same name, e.g. ubuntu.iso plus ubuntu.iso.aria2.
How to finish the download
Point aria2 (or your download manager) at the same folder and re-run the download. It reads the .aria2 file, sees what is missing, and continues. When the download completes successfully, aria2 deletes the .aria2 file automatically.
Is it safe to delete?
If you delete the .aria2 file you lose the ability to resume — you would have to download from scratch. If you have given up on the download, delete both the .aria2 and its partial file together to reclaim space. Deleting it never harms a completed file.
FAQ
Can I open an .aria2 file?
There is no reason to — it is internal resume data, not a document. Let aria2 use it to continue the download.
How do I resume with an .aria2 file?
Restart the same download in aria2 from the same folder; it reads the .aria2 file and continues where it stopped.
Is it safe to delete?
Yes, but you lose the ability to resume. Delete it with the partial file if you have abandoned the download.