Hi @anon62096739,
More information would be useful, see [HowTo] Provide System Information
However, according to this answer on Stack exchage:
There is a bug which matches everything you describe (including the separate comments when I wrote this answer). The bug was introduced in upstream kernel v4.14, which was fixed in v4.17 and v4.16.8.
If you still do not have a new enough kernel, and you don’t want to install an older kernel (switch to the
linux-lts
package mentioned in the Arch thread below?), there is a workaround. You can add the option “scsi_mod.scan=sync” to the end of your kernel command line, e.g. in GRUB.
I have no idea if it’s the same bug or if it’s something else, though.