The phenomena appears to relate to the write protect tab of the sd card adaptor
The virtual machine does not appear to be damaged.
When the write protect tab is in the write permit position, the directory structure of the partition can be examined.
When it is in the write protected position, you get a 3 way choice.(retry, continue, abort)
Abort leads to a crash an burn
A host reboot seems to be needed to recover from the crash and burn
There may be an alterntive recovery strategy, but I have yet to discover it
During the confirm experiment (the second time the write protect tab was in the write not permitted position)
The virtual machine disk was corrupted. When I attempted to power the virtual machine the Error message "The file specified is not a virtual disk" is reported.
SD drive was probably off-line as Windows device manager indicates (This device cannot start. (Code 10) ), yet I can format the drive using Windows storage administrator