[Computer Management] Storage > Disk Management.
[Computer Management] Right click 'Work Media 2'> Change Drive Letter and Paths…
[Computer Management] Add F:
[Windows Explorer] Delete old backup.
[VeraCrypt] Mount 'Content.tc' to M: drive (read-only).
[VeraCrypt] Create Volume
[VeraCrypt Volume Creation Wizard] Create an encrypted file container, Next
[VeraCrypt Volume Creation Wizard] Standard VeraCrypt volume, Next
[VeraCrypt Volume Creation Wizard, Volume Location] F:\New.tc
[VeraCrypt Volume Creation Wizard, Encryption Options] AES, SHA-512, Next
[VeraCrypt Volume Creation Wizard, Volume Size] 256
GB, Next
[VeraCrypt Volume Creation Wizard, Volume Password] Tick Use keyfiles, Next
[VeraCrypt Volume Creation Wizard, Large Files] No, Next
[VeraCrypt Volume Creation Wizard, Volume Format] Filesystem: FAT, Cluster: Default, not dynamic, Format
[VeraCrypt Volume Creation Wizard] Wait for an hour or two…
[VeraCrypt] Mount 'New.tc' to N: drive.
[Command prompt] xcopy M:\* N:\ /e /c /h /y
- faster than Sneaker Net Sync.
[Windows] Do a disk scan on N: drive.
[Sneaker Net Sync] Verify everything on M drive is the same as N: drive.
[WinMerge] Verify everything on M drive is the same as N: drive.
[VeraCrypt] Dismount all.
[Windows Explorer] Rename 'Content.tc' - '20180101 Backup.tc'.
[Windows Explorer] Rename 'New.tc' - 'Content.tc'.
[VeraCrypt] Mount 'Content.tc' to M: drive (read-only).
[Sneaker Net Sync] Re-index stuff, using hash values.