Question : Problem: Canon 340P unable to open twain source

Have a Canon 340P scanner with parallel connection to computer and another parallel connection to Canon BJC-2100SP printer.

Printer works fine.  Scanner doesn't.

Error message is Error code 0x10ff0800 and a message Unable to open twain source.

Scanner LIDE head lights up but does not seem to move at all.  The scanner is unlocked - have checked it both locked and unlocked positions but the symptoms and errors are the same.

LIDE head lights, seems to attempt to move and then stops.

Is it the hardware or the software?

Answer : Problem: Canon 340P unable to open twain source

set bios lpt port to ecp/epp for dual communication support.
What happens when you only use the scanner? if working
The combination you use might be incompatible then.
Else try to reinstall the scanner software
When you try to reinstall, make sure all the content of the scanner (twain drivers etc) are deleted.
if not, when the drivers are corrupted, and you tried to remove and reinstall, windows doesn't really
delete and overwrite the files.
Most times, you have to do this manually.
Justus