USB drive caused me heartache

Hi everyone. More a word of caution than anything, but here goes.

My friend has an unRAID server that I built and configured for him around 2 years ago. He uses it to stream his existing DVD rips in Plex and basically nothing else. I went to his house a few days ago and was helping him do some simple maintenance - checking warnings/cautions in 'Common Problems', cleaning out the dust, etc. When I finished and tried to boot, it just hung on POST and had no video output. He says: "Oh yeah, it does that occasionally and needs a reset or two to get it to boot."

I did all the basic troubleshooting: disconnect everything, clear CMOS, swap RAM sticks around, etc. Nothing helped - no POST, no boot, just fans spinning and a solid LED code for 'VGA'. I offered to take it home and swap in a spare board/CPU/RAM that I had lying around, then left.

When I get it home, I re-did the troubleshooting with no change, so I did the board/CPU/RAM swap. I confirmed my donor setup worked before doing cable management in his case, it worked, I did cable management, then tried to boot to confirm it sees drives and everything is stable and happy before returning it to him.

MY DONOR BOARD WOULDN'T POST and I finally connect the dots - the USB stick had some weird problem, neither of our boards could POST with it inserted, and I never tried removing the USB stick during troubleshooting. I swapped his board/CPU/RAM back in and it works fine.

Ooof >.<

My laptop could mount and read the stick, so I will be copying the config files and transferring the license. USB boot sucks and I wish there was another method. I ordered a [SanDisk MobileMate USB 3.0 microSD Card Reader](https://www.amazon.com/dp/B07G5JV2B5?psc=1&ref=ppx_yo2ov_dt_b_product_details) which supposedly works with unRAID.