Startup disk randomly disappears and reappears since installing Big Sur

[Lojzo]

I installed Big Sur when the public beta came out, no funny business, all official, and the installation went without a hitch (MacBook Pro, 2017)

However, often when waking from sleep I will get the flashing ? folder showing the startup disk is "missing". It's not every time, may 25%. To get it working again I try

• Safe boot (hold shift)
• Purge PRAM (cmd+opt+p+r)
• Remote boot (cmd+r)
• leaving it and trying again later (not short cut)

The effectiveness of these methods seems random. I will just cycle through them until something works. I tried reinstalling BS but when it was ready to install the was no disk to instal it to, so it failed.

each update I hope things will be magically fixed, but so far, only disappointment.

I guess it could be a faulty SSD but when it starts up, everything works perfectly.

Will attach a video (I hope) that perfectly shows what the title states.

If anyone has had similar issues I would be grateful for support and advice. Thanks in advance.

 

[IowaLynn]

Cloning tools are no help. I would invest or get out a spare backup to use to test fresh setup and in case your drive is in fact failing or has an issue with pre-boot partition