The memory stick does not appear on my computer

[Omputer]

When I plug a memory stick into the USB port  ( the All-in-one 24 eOXX computer) , the stick doesn't appear in Files Explorer (nor in Device Manager), so I cannot open it. Have been working for years. Memory sticks does not work on any USB port, all other devices are working. The sticks work on another similar computer. so there should be nothing wrong with them.

[BeemerBiker]

Try the following:

Disable fast start to make sure you do not use an old image that has the USB problem.

https://help.uaudio.com/hc/en-us/articles/213195423-How-To-Disable-Fast-Startup-in-Windows-10

then shut the system down fully where the power is off and it is not in hibernate or sleep mode.

On some systems, like my surface pro 4, a windows shutdown does not actually turn it off and one has to do a hard reset.  I do not know how your AIO handles shutdown.

If the above does not work then create a new admin account, log out of you account and log into the new account and see if that fixes the problem.