Window Clipping in Coherence Mode.

L

LorenM1

Bit poster
I am running Windows 11 on Parallels on my Mac Studio (15.7 and 26.0.1) in coherence mode. It has been smooth sailing for almost a year; until just this past week.
Now, whenever I open an email in Outlook running on Windows in Parallels in coherence mode the email window gets clipped, only showing on existing Parallels Windows apps windows until I click on it on the edge or the info area, then it shows up in full. See the image below... When Parallels is not in coherence mode (windowed/full-screen) the clipping does not happen.
I have checked outlook settings and do not see anything that could cause GFX/display issues.
My Mac had been on Sequoia (15.7) for about 2 weeks when this clipping started.
Parallels just notified me of an update today so I updated that and rebooted the Mac. The problem was not resolved.
I thought it might be the Mac and went ahead and updated to Tahoe (26.0.1) but that also did not resolve the issue.

NOTE: I did have an issue where one of the two monitors was not being detected by the Mac about 2 weeks ago. I don't think that is related but I figured I would mention it since its display related.


upload_2025-10-16_14-54-54.png
 
Following this thread. I am having the same issue. I am on Tahoe and 24H2. All of the Mac/Parallels/Windows updates have been applied. Issue still persists.
 
Hi,
I experienced the same issue and traced it back to the KB5066835 Windows update, which is known to cause problems. After uninstalling it, the issue disappeared. I've already reported it to Parallels support. It would be great if you could do the same, as the update will eventually try to reinstall itself. A permanent solution needs to be found to prevent this from happening again.
Here is a video how to uninstall the update:
 
It sounds like a display glitch caused by the recent macOS and Parallels updates. Since it only happens in coherence mode, try adjusting the display settings in Parallels, like resetting the scaling, turning off "Optimize for Retina," or toggling the "Always hide Mac menu bar" option. If that doesn't fix it, reinstalling Parallels Tools often clears up these kinds of window clipping issues after updates.
 
JimA6 said:
It sounds like a display glitch caused by the recent macOS and Parallels updates. Since it only happens in coherence mode, try adjusting the display settings in Parallels, like resetting the scaling, turning off "Optimize for Retina," or toggling the "Always hide Mac menu bar" option. If that doesn't fix it, reinstalling Parallels Tools often clears up these kinds of window clipping issues after updates.
Click to expand...
Hi JimA6,
I've tried all of the measures you suggested. As mentioned above, the issue may be related to the Windows Update KB5066835, because an uninstall solved the issue. Reinstalling the update has resulted in the problem recurring.
Did any of the steps you described help resolve the issue with your configuration? If so, which specific adjustment led to the resolution?

Best regards
 
Greetings,
Thank you for your feedback.
We'd like to inform you that this is a known issue, and our Development team is actively working on a permanent fix.
In the meantime, the recommended workaround is to uninstall the Microsoft Windows Security Update KB5066835 from the affected virtual machine. This has been confirmed to resolve the issue for many users while we finalize a long-term solution.
Thank you!
 
Hi Avinash
Thanks for this information. I have been experiencing the same issue. Uninstalling the Microsoft Windows Security Update KB5066835 and then reinstalling Parallels Tools has fixed the issue, at least until my machine attempts to reinstall the security update again. Hopefully you are able to deploy a long term solution very shortly.
Kind regards
Mark
 
Avinash Bundhoo said:
Greetings,
Thank you for your feedback.
We'd like to inform you that this is a known issue, and our Development team is actively working on a permanent fix.
In the meantime, the recommended workaround is to uninstall the Microsoft Windows Security Update KB5066835 from the affected virtual machine. This has been confirmed to resolve the issue for many users while we finalize a long-term solution.
Thank you!
Click to expand...
Hi Bundhoo,
just checking in to see if there's any update on this issue. I've updated to the latest Parallels Desktop 26.1.2 (57293), but unfortunately the problem still persists on my side.
Since we have to stop Windows updates to avoid triggering the issue, a permanent fix would be really helpful soon. I'm using Parallels exclusively in Coherence Mode and rely on it for my daily workflow, so a stable solution is quite important.
Thanks a lot in advance for any update!
 
I've both removed the KB update and updated Parallels, and I continue to have issues. Its prevalent in Offce 365 apps in particular. Windows just don't even show. For example if I create a new email or appointment, that window shows nowhere. In word, creating a new document also shows nowhere. Really a productivity buzz saw.
 
I too have the same issue. I opened cmd with elevated permissions and ran:
wusa /uninstall /kb:5066835
It states this KB wasn't found.
I've reinstalled Parallels Tools several times. Nothing works! I am forced to use Parallels in full screen on one monitor rather than coherence mode. Totally frustrating!
 
Avinash Bundhoo said:
Greetings,
Thank you for your feedback.
We'd like to inform you that this is a known issue, and our Development team is actively working on a permanent fix.
In the meantime, the recommended workaround is to uninstall the Microsoft Windows Security Update KB5066835 from the affected virtual machine. This has been confirmed to resolve the issue for many users while we finalize a long-term solution.
Thank you!
Click to expand...

Hello,
I'm still experiencing the issue. After suspending Windows updates for about five weeks, Windows prompted me to restart due to a pending update. I suspended the updates again, but the clipping problem has now returned. At the moment, my only workaround is reverting to an older snapshot.
Is there any update on a permanent fix?
I rely heavily on Coherence mode in my daily workflow, so a stable solution would be greatly appreciated.
Best regards,
Bob
 
I'm having the same issue and don't have KB5066835 as an option to uninstall. I have tried all the different graphics options - scaled, external, retina. None of them fix the problem when using an external monitor.
 
I had used the KB5066835 uninstall workaround and was good for a while but I didn't pay attention and windows switched back on auto updates, updated and the issue reappeared. Like the user above, KB5066835 was not available.
After some trial and error I found uninstalling KB5068861 appears to fix the issue again.
 
LorenM1 said:
I had used the KB5066835 uninstall workaround and was good for a while but I didn't pay attention and windows switched back on auto updates, updated and the issue reappeared. Like the user above, KB5066835 was not available.
After some trial and error I found uninstalling KB5068861 appears to fix the issue again.
Click to expand...

Again ... another instance of KB5068861 is not installed on my virtual machine and not in the list of updates that can be uninstalled
Screenshot 2025-12-09 at 17.31.18.png

Screenshot 2025-12-09 at 17.33.21.png
 
LorenM1 said:
I had used the KB5066835 uninstall workaround and was good for a while but I didn't pay attention and windows switched back on auto updates, updated and the issue reappeared. Like the user above, KB5066835 was not available.
After some trial and error I found uninstalling KB5068861 appears to fix the issue again.
Click to expand...

I have literally uninstalled every update it will allow me to, but even though it has an uninstall button, it won't let me do it to KB5070300. It fails every time. I don't know if this affects Outlook, but I've deleted everything else.
 
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