What Is a .DOWNLOAD File?
Safari left a .download item in your Downloads folder and the real file never appeared. It is an unfinished download. Here is how to fix it.
What a .download file is
On macOS, a .download is actually a package Safari uses for an in-progress download. While bytes are arriving Safari stores them here; when it finishes, the real file appears and the .download disappears.
Why it is stuck
Safari was quit, the network dropped, or the download was paused and lost. The partial data is inside the package but not yet a usable file.
How to finish it
Open Safari and press Cmd+Option+L to show Downloads, then click the resume (circular arrow) button. If the entry is gone, start the download again.
Is it safe to delete?
Yes, once you have given up on it. Move the .download to Trash; you only lose the incomplete data.
FAQ
Can I open a .download file?
No. It is an incomplete Safari download package with no usable file inside yet.
How do I resume a Safari .download?
Open Downloads (Cmd+Option+L) and click the resume button, or restart the download from the page.
Is it safe to delete?
Yes, if the download is dead — you only discard the partial data.