Weird Windows 11 bug that messed up Task Manager gets a fix.

Some Windows 11 users recently encountered a bug with a preview update whereby the Task Manager could end up being displayed in different colors, possibly rendering it unreadable – but the good news is Microsoft’s most recent patch has fixed the problem.

This issue was introduced in the optional update (a preview, meaning it’s still in testing) for Windows 11 that arrived late in November (KB5020044).

It caused Task Manager – the panel that shows your running processes, and a bunch of other details like resource usage (CPU, memory, GPU and more) – to become “unexpected colors” in some parts of the interface, potentially meaning the info therein couldn’t be made out.

It’s one of the weirder Windows bugs to manifest in recent times, certainly, and while not a show-stopper, it’s certainly an irritation if it does obscure something you want to actually see. According to Microsoft, it affected those who had chosen custom mode in Personalization > Colors under Settings.

As Bleeping Computer reports, the good news is that with the latest Windows 11 cumulative update, KB5021255, which was pushed out earlier this week, the problem has been ironed out.

Windows 11 users should have been offered KB5021255 for download at this point, but if not, simply head to Windows Update and check for new updates, and it should be there by now.

It’s no great surprise to see a bug introduced by a preview update. These updates are optional precisely because they’re in testing, and it’s only wise to install one on your main PC when it remedies a problem that’s really causing you grief. Because these updates can fix something with one hand, and break something with the other, which is exactly what happened here (gaming bug fixed, then Task Manager, well, not broken but certainly behaving badly in some cases).

Of course, it does not just preview updates that can unintentionally bust bits of Windows. As we’ve seen in the past, even release updates can have alarmingly serious bugs (that’s certainly the case with Windows 10, although we’ve not seen anything quite as bad as the file deletion glitch with Windows 11).

At least in the case of this Task Manager gremlin, the bug won’t have hit that many folks, as it’s a niche number of users who install a preview update, and those that did had to have changed the aforementioned setting (and even then, it didn’t affect everyone). Furthermore, the remedy arrived quickly, in fact just a couple of weeks after the bug was uncovered.

Anyone running test software – whether Windows Insiders who have preview versions of Windows 11 installed or those on the release version of Windows 11 who use optional updates – must be prepared to encounter additional bugginess levels over and above the norm.