Just started in the last 24 hours , at least that I have noticed. When doing a custom clean , after cleaning on section like a browser cache , about 5 seconds afterwards the screen flashes. Have not seen this in any other programs on the system. Any clues?
Without further description of “flash” I’d geuss at a desktop icon refresh?
Those can happen after cleaning some things, such as the Recyle Bin where the icon changes after the bin is emptied.
Instead of just changing one icon Windows will refresh the lot which can look like a flash of the whole desktop.
It tends to be more noticable on certain machines, and sometimes on certain Windows builds so can suddenly become noticable following a Windows Update.
Hi Jeff_M:
Your screen flash might be related to the bug reported in yomama’s 26-Mar-2025 CCleaner ver 6.34.11482 freezes computer for 10-15 seconds after cleaning finishes.
Dell Inspiron 15 5584 * 64-bit Win 10 Pro v22H2 build 19045.5608 * Firefox v137.0.0 * Microsoft Defender v4.18.25020.1009-1.1.25020.1007 * Malwarebytes Premium v5.2.9.176-129.0.5196 * Macrium Reflect Free v8.0.7783 * CCleaner Free Portable 6.34.11482
The flash looks like a someone took a flash photo , but the system does not have a camera. Watching closer , the screen goes to gray for less than a second giving the appearance of a flash.
The system is Win10 Pro , 8 gigs memory , and a 1 terabyte HD. All programs are up to date. I tried reinstalling CCleaner , but still get the same flashes several seconds after a cleaning operation. Only happens in the custom clean in CCleaner. CCleaner is full screen.
Just read that post. It does sound like it may be related.
no one asked yet, are you using custom clean or health check?
Custom Clean - stated in the initial post.
so it is, sorry bout that totally missed it. Are you using a custom winapp2.ini? do you have anything checked for cleaning aside from the defaults?
Just using the standard settings as the program installs.
Forgot to include the version of CCleaner - 6.34.11482.
One thing just noted is that the flash after a cleaning operation only occurs if you hesitate a couple of seconds. If you immediately go on to clean the next desired area , no flash.
One other thing that might be the cause is that a few days ago , Intel did a graphics update.
I’ve eventually got around to firing up a Win 10 laptop to look into this, with some interesting results.
I let it do all the pending Windows (and other) Updates and then opened CCleaner FREE v6.33.
NOTE that the testing below is all happening with CCleaner Free v6.33, which rules out it being something that was changed with CCleaner v6.34.
Some seconds after opening CCleaner v6.33 all of my desktop icons refreshed (went blank and then came back).
That had not happened before, now it seems to be happening more often than not when I open CCleaner 6.33 on that Win 10 machine. (The time between opening CCleaner and the Desktop icon refresh varies, which seems odd).
However that isn’t what was being described here so I carried on testing.
Next I tried a right-click clean of just one option in Custom Clean (I did the Edge Chromium ‘Session’).
That ran and then after about 5 seconds the CCleaner UI flashed grey, exactly as has been reported - BUT THEN I was shown this ‘get an upgrade’ nag screen:
Further cleans, even a full ‘Run Cleaner’, resulted in a quick greying ‘flash’ about 5 seconds after each clean, but the nag screen was not shown again.
Even after closing CCleaner and re-opening it there was no nag, - The nag will be on a 'once shown don’t show again for so many days’ timer which is why you only see it the one time.
This odd behaviour may well be due to a Windows graphics update, but I’m not so certain that it’s Intel
I can see this issue on my Win10 laptop, which has Nvidia graphics. (Quadra NVS 130M).
It is not happening on my Win 11 laptop, which has Intel graphics. (UHD Graphics).
EDIT 1 -
As the grey flash-screen appears to be associated with that nag screen I tried a further test - I registered that v6.33 as Pro rather than Free.
As I suspected would happen that stops the flashing happening, because there is no reason to show you that ‘upgrade’ nag screen if your CCleaner is already Pro.
Reverting it back to Free and the grey flash-screen after running any a clean starts again.
(However I wouldn’t be surprised if some other pop-up screens in Pro might also trigger it).
EDIT 2 -
It doesn’t happen with Health Check (or at least I can’t make it happen with Health Check).
I believe that HC uses a different, more modern graphics programming and commands than Custom Clean does, I seem to recall some previous display issues happening because of that difference.
BTW. I have now updated the CCleaner on my Win 10 machine to v6.34 Free.
It is still showing the grey flash-screens after a clean. (If I upgrade it to Pro they stop).
I suspect that you are correct that it is a graphics issue. My system has Intel graphics only and that was recently upgraded. The issue would seem to be a clash between something in CCleaner and the graphics on the system.
I have never seen that nag screen , BTW.
Out of interest does the flashing still happen if you first disconnect from the internet, then open, then run ccleaner?
I can’t see that as making a difference. The issue was not there until the graphics were updated. Never happened before that.
I didn’t test it offline, so can’t see if a connection is triggering it, but I think it’s more likely to be a local command doing it because of those old style graphics routines.
Let’s face it the original Custom Clean graphics handling routines were written some years ago.
My conclusion as well. Something in the Custom Clean is being affected by recent graphics updates (Intel on my system).
Update, and the NVIDIA/Intel graphics may also be a red herring.
Other that the fact that it’s happening on my NVIDIA machine would appear to rule out it just being an Intel Update issue.
I’ve just tried again on this Win 11 machine, and it is now also showing the grey flash-screens, and the nag screen the first time.
Some are very, very, quick on this machine so maybe I had just missed them before?
So I’m now seeing it with both NVIDIA and Intel graphics (and both Win 10 and Win 11).
I’m only seeing it in CCleaner Free and not in Pro.
I’m only seeing it in Custom Clean and not in Health Check*.
@hazelnut I remembered to try, and being offline makes no difference, the ‘flashes’ still happen following a clean even when offline.
*There has also been a post today with a report of something that sounds similar possibly happening in Health Check.
But I’m not sure just what the poster is reporting, it doesn’t sound like an on-off flash, and he says he has a screenshot of the greyed screen.
I’ve asked for more details.
Interesting. keep us posted on findings. Could still be a graphics issue that both Intel and NVIDIA both use.
The Health Check one now appears unrelated, that’s been clarified and it’s just a single button that is not working there.