Mount error with persistence file

[avggeek]

It seems like it's an issue with using persistence files with Ventoy booted via VirtualBox.

I tried both ubuntu2110.dat (persistence_ext4_1GB_casper-rw.dat) and persistence_ext4_512MB_casper-rw.dat with Ventoy booted from a physical machine and the persistence files worked correctly. 

Might be worth mentioning in the plugin docs for folks who are using VirtualBox to test their Ventoy config.