virtualbox_datetime_offset.ps1

# Change the location to the VirtualBox installdir; default is used here
Set-Location "C:\Program Files\Oracle\VirtualBox"

# Get a list of VMs
 .\VBoxManage.exe list vms
 
 # Determine the off-set required; modify date as needed
 
([datetime]"07/01/2019" - [datetime]::Now)

<# Example output:
PS C:\Program Files\Oracle\VirtualBox> ([datetime]"07/01/2019" - [datetime]::Now)


Days              : -141
Hours             : -11
Minutes           : -54
Seconds           : -25
Milliseconds      : -889
Ticks             : -122252658893519
TotalDays         : -141.49613297861
TotalHours        : -3395.90719148664
TotalMinutes      : -203754.431489198
TotalSeconds      : -12225265.8893519
TotalMilliseconds : -12225265889.3519
#>

# Change the off-set to the ms value from above
 .\VBoxManage.exe modifyvm {vmname} --biossystemtimeoffset -12225265889