Access to folder denied for no reason Help

I’m streaming off a flash drive on my computer. I tried to watch a show on my tv and it said it was unavailable when I KNEW that the MP4 was still in the folder linked to that library. I went to my computer and I kept getting “location is not available” “access is denied” errors when trying to access that one folder on my flash drive. Right clicking on the drive and selecting properties does not show a security tab. I could get into all of the other folders on that drive just fine and those other folders were also connected to plex libraries. I restarted my computer and the folder I was being denied access to had completely disappeared when I checked the flash drive. I am EXTREMLY annoyed about this. I’d like to ask how to keep it from happening again but I’m not that savvy with computers and chances are that I’ll have absolutely no idea how to do whatever people tell me to do to fix this. Also earlier today I tried watching my stuff on my TV and all of my shows were just a black screen with audio but no video and I had to restart my computer to fix it - I looked up how to fix it and it said to go into the transcoding settings and uncheck an option that doesn’t appear despite being in the exact place that was shown in a picture showing where that option is - this is all EXTREMLY frustrating to me and I NEED a “for dummies” explanation on how to keep these things from happening again

Let’s maybe start with something simple…
On what kind of operating system (incl. version) are you experiencing this (e.g. Windows, Mac, Linux)?

What version of Plex Media Server is currently installed/running on that system?

I’m using Windows 11 Home

My Plex Media Server is verison 1.41.9.9961-46083195d

I got the black screen with audio but no video again tonight and restarting my computer didn’t fix it this time.

The version on my TV is Plex for Vizio, Client Version 5.93.2, Platform Version 3.3.3-2519.0002, Chipset MTK-5691

Edit: enabling “force direct play” on my TV fixed the issue with the black screen, for now at least