Hi dominic. Thanks. I had already reviewed that article however I recall that at my last visit to the apple Genius Bar the agent recommended that I avoid file vault because of issues which could corrupt data. For instance he mentioned issues associated with limited disk space which could corrupt data as well as bad sectors and if corrupted no one coils recover the data.
Is there a simpler way to have a strong password to protect an external HD from access by unauthorized persons without having to encrypt all data on g drive before time machine backs it up to the ext HD?
Issues with limited disk space or bad sectors can happen with or without FileVault. FileVault will however make any recovery attempt harder; some recovery tools may not support it. You should always have backups, nevertheless.
You can re-format an external harddrive with an encrypted filesystem. Select the drive in Disk Utility, select the Erase tab and select a Format which is encrypted.
The Apple Genius was conflating two things. Filevault will not corrupt any data, but it will give you issues if you attempt to repair corrupted data.
Here is the issue: In the event that your filesystem becomes corrupted, you cannot repair your boot drive's file system from the recovery partition with filevault enabled. You must disable filevault first before fixing a corrupted file system on the primary (boot) partition.