I run armory on an external 2TB hard drive.
....
(WARNING) SDM.pyc:396 - Spawning DB with command:./ArmoryDB.exe --db-type="DB_FULL" --cookie --satoshi-datadir="A:\_Data\_bitcoin-core\blocks" --datadir="C:\Users\lac\AppData\Roaming\Armory\" --dbdir="C:\Users\lac\AppData\Roaming\Armory\databases"
(ERROR) ArmoryQt.py:1188 - 3 attempts to load blockchain failed. Remove mempool.bin.
(ERROR) ArmoryQt.py:1193 - File mempool.bin does not exist. Nothing deleted.
....
I think your pathing is screwed up, unless A:\ and C:\ refer to your external drive.
See
https://btcarmory.com/docs/pathing