On my gaming PC build 3 years ago I installed this week Windows 11 ... I used simple OS update which went smooth, but as you may guess, there is some issue. For me it is about non-functional USB 3.1 Gen 2 port which was in windows 10 regularly working and I even used it for download W11 install files. Immediatelly after W11 installation/restart it stopped working. I contacted my MB manufacturer (MSI) and asked if there is any known issue. During emails exchange I used manual (ha, this was surprisingly a good idea ) and it helped me identify that non-working USB is Gen2 which I had no idea before. MSI also told me that they do not have drivers for this (ASMedia USB) and that it comes from Microsoft. They also told me that clean W11 installation on theirs side on the same motherboard (MSI Z370 TOMAHAWK) have that USB port correctly working. This leaves me 2(3) options: wait for update from microsoft (*technician suggested wait for few weeks since there should come some updates by his words) ... or go for clean W11 installation ... or ignore that issue (I can, but I do not want to :D).
*Today I contacted local Microsoft office and asked technician if W7 key (there is older discuss about this here and here). will work if I used it for move from W7 to W10. He replied that it still is possible ... well I guess will find soon (later this week), if that info is reliable. I also saw on reddit that there also some other people have USB ports issues after W11 installation, but what I have read so far is mostly for general issues with USBs and not specific cases for one of USB versions.
Any advices for this matter would be welcomed ... I'm not much happy with idea about reinstalling my whole gaming PC, but it can be possible better in long view and allows avoid any further issues with possible leftowers from W10.