'Any ideas?' - ...
Consider using '
SuperDuper' (freeware / shareware [more features]) to copy the bootable external hard disk drives', hdd, installation onto the internal hdd.
01. Boot from the external hdd.
02. Download 'SuperDuper' (onto the external hdd).
03. Perform a 'Copy' from the external hdd onto the internal hdd.
04. From the 'using' popup menu, select 'Backup - all files'.
05. Click on the 'Options...' button
06. From the 'During copy' popup menu, select 'Erase <internal hdd name>, then copy files from <external hdd name>'.
07. From the 'On successful completion' popup menu, select 'Restart from <internal hdd name>'.
08. Click on the 'OK' button.
09. Click on the 'Copy Now' button.
'
Carbon Copy Cloner' (freeware) is also a possibility.
If you do perform the above steps, or similar, please post your results.