Mine fails to boot too. My message is slightly different though: Load system Resizing disk(GPT)... ERROR: could not mount disk! Please attach it somewhere else. For those seeing these GPT errors - you have to give the VM more HDD space. For me I had mine set to the default? 64MB. I increased to 256...
I had a test CHR on VMware ESXi 6.7 running 7.1beta4 with a quite simple config (1 interface, fixed address, a BGP session) I used System->Packages upgrade to load 7.1beta5 It fails to boot now. On the console it says: Load system WARN: GPT: skip truncate ERROR: could not mount disk! Please attach ...
For me, too, due to the ntp package, the ARM architecture cAP ac was restarted randomly.
Once I turned off the ntp package, it has been stable ever since.