You open Task Manager because the computer feels slow and find a process you never installed: Acrobat Collaboration Synchronizer, or AdobeCollabSync.exe. It belongs to Adobe Acrobat and Acrobat Reader, it is normal, and in most cases it is harmless. This page explains what it does, whether you need it, and the safe way to stop it running at startup.
What Acrobat Collaboration Synchronizer does
It is a background helper that ships with Acrobat and Acrobat Reader. It keeps data used by Adobe's online features in step with your computer: shared PDF reviews, the recent-files list, notifications and the Adobe trust list among them. It keeps local copies of that data so Acrobat can still show it when the server is out of reach. Several instances can appear at once, which is normal.
Is it safe?
The genuine file lives inside the Adobe installation folder, for example under C:\Program Files\Adobe\. If the process runs from that folder and uses little CPU and memory, it is the real Adobe component. If it runs from anywhere else, or you are not sure, scan the file with your antivirus before doing anything else.
Should you disable it?
| You use… | Recommendation |
|---|---|
| Shared reviews, Adobe cloud storage or signing in Acrobat | Leave it running. Those features rely on it. |
| Acrobat only to open and print local PDFs | You can stop it from starting with Windows. Acrobat still works. |
| It is using high CPU or crashing | End the task once to confirm it is the cause, then update or repair Acrobat. |
How to stop it running at startup on Windows
- Open Task Manager (Ctrl + Shift + Esc).
- Go to Startup apps (Windows 11) or the Startup tab (Windows 10).
- Find the Adobe Collaboration Synchronizer entry, if it is listed, and choose Disable.
- Restart and check Task Manager again.
What not to do
- Do not delete or rename AdobeCollabSync.exe. It can break Acrobat, and the next Acrobat update puts it back anyway.
- Do not rely on old tricks such as pausing Creative Cloud file sync; they do not stop this process.
- Expect updates to undo changes. After a major Acrobat update, check the startup list again.
If Acrobat itself is the slow part
A background synchronizer rarely makes a computer slow on its own. When opening PDFs is what feels slow, especially large construction or engineering drawings, the viewer is usually the bottleneck rather than a helper process. That is the problem we built Ncored for in our architecture studio: a desktop PDF editor for Windows and Mac that opens drawing sets of 50 MB and more fast and stays smooth on zoom and pan, with no background sync service and no cloud upload. See how a dozen PDF editors handled one heavy drawing in our stress test.
Frequently asked questions
What is AdobeCollabSync.exe?
The Acrobat Collaboration Synchronizer, a background component of Adobe Acrobat and Acrobat Reader that syncs data for shared reviews and Adobe's online features.
Why are there several AdobeCollabSync processes?
Acrobat starts more than one instance of the synchronizer. Several entries in Task Manager are normal.
Can I remove Acrobat Collaboration Synchronizer?
Not on its own. You can stop it from starting with Windows; removing the file can break Acrobat and updates restore it.
Does it upload my PDFs?
It syncs data for features you use, such as shared reviews. If you do not use Adobe's online features, there is little for it to sync.
Related: why Acrobat is slow even on a powerful PC, why PDFs are slow with construction drawings, how to change the default PDF viewer.