Well like last month every time at system startup, it was notifying me that a threat was detected. If I click the notification or open Windows Security, then there was nothing there, nothing in protection history also. It was happening on every system startup and reboot. I was pretty sure that my system was not infected but of course it worried me a bit. Multiple second opinion scans didn't find anything. Thinking it was another Windows Security UI bug, I tried to delete files in "C:\ProgramData\Microsoft\Windows Defender\Scans\History\Service" which is a trick to delete Defender's protection history. In the past you could delete these just by turning off Tamper Protection but that doesn't work anymore. So, self-defense has improved, I guess. Deleted the files by rebooting to safe mode. Still one log file couldn't be deleted. Anyway, I rebooted my PC normally, same notification from MD but this time I could see what it has detected. It's an app from NirSoft Utillities named, "Wireless Network Watcher". This time MD detected and auto deleted it but of course not before I applied the trick of deleting protection history which not many people know about. I had a shortcut for it on start menu, that's why it could detect it at system startup even though I had it in my HDD drive. It's a helpful app that let me see what devices are connected to my network without having to log into the router. I can even name the devices whatever I wish. Nice little tool. Microsoft has recently added it to the PUP list something which ESET also has added to their secondary PUA detection. Maybe it was used in some attacks? But it's completely safe to use. Maybe you already know about it.
So, what if it was a real malware that MD could not delete for whatever bug that going on? Users could get infected.
Cloudflare Warp app runs with 3 seconds delay. I had to put the exe into exclusion to make it run fast. One portable downloader that I sometimes use still occasionally runs with 2-3 seconds delay even though I put it into exclusion. Lately even archives opened by 7zip beta opening after 2 seconds. There are some apps like this that I have to add to exclusion to make them run quickly which is not required for any other products except with F-Secure there was maybe still is an issue where it runs any unsigned app several seconds later after every signature update. MD also often deletes password malware zips downloaded from public malware sharing sites which is frustrating.
So, there goes my list of annoyance with Microsoft Defender.