Still happening. Using PRO. This is 100% an Adobe issue since killing the AdobeCollabSync unlocks files. I am not paying for unwanted cloud functions. I am paying for a product that just works ... and this is broken.

Fix it!

2/12/2022 This is also happening on Windows 11 with Adobe Acrobat Reader DC Version 2021.011.20039 64-bit

Even without Windows explorer preview turned off, the bug happends all the time.
I confirm this happends after closing acrobat and when NO INSTANCE OF ACROBAT IS CURRENTLY RUNNING.
Which is honestly a bit outrageous, someone who doesn't know how to manually kill running process would have to restard computer entirely just to rename a PDF.

We generally have to kill any "Adobe AcroCEF" and "Adobe Collaboration Sync" running process.
When in doubt, kill every Adobe running process.

Then we regain control over the file : renaming, moving, deleting, overwriting the file itself or parent folders.

Also I think we should be able to use explorer preview on windows... release file lock when not previewing the file ? don't lock the file when it's only a preview ?

It has been reported and discussed on many threads on community forums (One of which has over 17k views since 2017... 2017 !)
https://community.adobe.com/t5/acrobat-discussions/permanently-disable-adobe-collab-sync/m-p/12648210#M345108
https://community.adobe.com/t5/acrobat-discussions/we-re-going-to-mars-but-i-have-bigger-plans-in-2022-i-want-to-rename-a-pdf/m-p/12648217#M345109
https://community.adobe.com/t5/acrobat-reader-discussions/disable-file-lock-on-adobe-reader-dc-windows-10/m-p/12661753/page/2#M87519

This page showed up in my search when I was originally researching the issue, so my comment, below, is directed more at other folks who may end up on this page. I understand the root cause is different, in your case, NA. Good luck finding a resolution.

I don't see how FireFox can be involved when I don't use FireFox? The processes that hold the file open are both Adobe executables present in C:\ProgramFiles (x86)>Adobe>Acrobat DC>Acrobat folder (and \AcroCEF sub-folder), as evidenced by Windows Resource Monitor indicating it is these processes that still have a handle on the PDF file that has been closed in Acrobat. When renamed (e.g. AdobeCollabSync-PEST.exe) so it can't run, the file-lock issue never occurs again until Adobe releases an update and the file is reinstated. So it's a constant game of disabling these pointless processes after every Adobe update just so I can use Acrobat like any other program without interference.

When we experienced this issue, we traced it to a bug in Firefox ESR - https://bugzilla.mozilla.org/show_bug.cgi?id=1642951

Once we upgraded to a newer version of Firefox, the issue disappeared.

I too have this problem, and this issue has plagued Acrobat for many years. External software cannot rewrite a PDF file even after the file has been closed in Acrobat. Even closing Acrobat itself does not always solve the issue. An examination in Windows Task Manager shows it is the processes AdobeCollabSync.exe and/or AcroCEF.exe that is/are keeping a handle on the file even after after it has been closed in Acrobat. Only ending these processes in Task Manager releases the lock on the PDF file and allows external software to delete/rewrite the PDF file.

Hi Arpit,

Info as requested:

Windows 10 Pro N, 64bit Version 1903 - Build 18362.836
Showing as up-to-date just now.

Acrobat Pro DC: Continuous Release version 2020.009.20063
There was a recent update, so might have fixed now,,,

This seems to be an intermittent issue. I cannot reproduce the error at the moment it seems.

FYI...
Last situation was as follows:
- Win Explorer open, showing folder with PDFs
- Preview pane closed (had been open previously)
- 2-3 PDF files open in Acrobat Pro DC (sepearate paths)
- Commenting in one PDF
- Closed tab of that PDF, Saved.
- Showed other open PDF tab (normal)
- Attempted to rename the parent folder in Win Explorer.
- Retry failed.
- Closed other Win Explorer (known problem in Windows)
- Rename - Retry failed
- Close Acrobat Pro DC
- Folder rename Retry - successful.

However, this is not conclusive, I suspect Windows was 'beginning to fall over' as sometime later, some apps were misbehaving, and Windows needed to be restarted!

** I will monitor the situation over the next few days and report back any issues.

Thank you.

Hi lee,

Can you please also confirm the windows version on which you are currently. Also Can you provide us with the exact steps you are performing which is causing the issue at your end if there are some particular steps,

HI Lee,

Thanks for reaching out to us. Does the Issue is happening at your with the latest updates i.e May Release or was there in older releases as well. Also can you please tell how frequent the issue is at your end.