[FIXED IN 2.3.2] CustomBlur (IComposition) is broken on build 26x00.7019 (KB5067036) and later

[YMica-OSE]

Describe the bug:

After updating to build 26100/26200.7019 (KB5067036 aka the 2025-10 Preview CU for Windows 11 24H2/25H2), the default CustomBlur method no longer works properly, instead only showing clear transparency (no blur, no aero, just the color).
Title bars & window frames affected by the Override DWMAPI effect does not exhibit this issue.

To Reproduce:

Just install update KB5067036.

UPDATE - To fix:

Update to version 2.3.2.
Do note that at the moment this is still in beta, so do expect other issues. The fix may also require you to install the 26200 (25H2) enablement package - KB5054156.

Screenshots & Demo:

OBS_2025-10-30_17-32-43_Mica.mp4

Additional information:

• OS Version Tested : 26200.7019
• Software Version : 2.3.1

What other third-party software do you use:

None

Additional context:

From other related reports, it seems whatever change that caused this and similar bugs was introduced a few updates before this one, so the affected builds could range from 26x00.6972 to 26x00.7019+.
Other reports with this same issue: #597, #595, #608, #609, #617, #618

[LeeBinder]

see my comment #595 (comment)

[Pamlau]

Because of that windows update, my transparency does work but if the screen isn't focused (clicked in) it gives a white transparent screen

[UnfallenSeaMoon]

I have the same problem.Please remind me if this problem is fixed

[Sostay]

same issue

[0-BlackSpectrum-0]

Same issue, I'm on Windows 11 25H2, some apps like old windows image viewer, winaero and other apps have just transparent effect instead of mica which I've selected, whereas some modern windows app like new snipping tool, paint,etc have the mica effect, I just installed this app yesterday, and running latest version of it as of 9 November 2025.

I also use your Explorer Mica effect app and Windhawk, if it helps

[Pamlau]

Hey guys, I wanna point out that I fixed mine simply by adjusting the opacity back to 0%, it has always been at 0% but for some reason with the windows update it set it to 50% opacity or so, maybe try readjusting the settings again just to make sure

[Sostay]

Hey guys, I wanna point out that I fixed mine simply by adjusting the opacity back to 0%. It has always been at 0%, but for some reason with the Windows update it set it to 50% opacity or so. Maybe try readjusting the settings again just to make sure.

It helps a little, but this is clearly not the perfect solution. I think the tool might need an update

[jgalvez21]

I also have this issue, sadly transparency to 0% did not work

[L3-NR]

Same issue here, it seems that windows update broke it.
Aso, saving the config was also broken with the same windows update.
If you change a setting, press the save icon, and restart the application, your settings do not persist anymore. At least on my env.

[BothSamuel]

The only temporary solution is to use Mica For Everyone, and in the "Global" rule, change the Background type to "Acrylic". At least in my case, I'm still using DWMBlurGlass to configure the title bar color, blur level and set the title bar buttons to small, like in Windows 7.

Mica for everyone config

[jgalvez21]

mica foreveryone i cannot get it to work on firefox... toolkit.legacyUserProfileCustomizations.stylesheets