The MICR line for a personal check looks *something* like this:
t012345678t0123456789t 001001
o = Onus symbol
t = transit symbol
In the above MICR line, the check number is the 001001 portion, so when you enter in the "Check Number" in Edit -> Edit Account, you should put that number. (This does not mean to literally put in 001001, but put whatever number is actually on your check, in that position.
Attached below are examples of both a Personal and Business MIRC lines.
If you are copying this MICR line off of a temporary checks this could be a problem, because temporary checks do not have check numbers on them. The program does not know where to put your check number. You may want to make up a number in the MICR line and enter that same number in the check number field.
The MICR line for a business check looks *something* like this:
o543123o t123456789t 987654321o
o = Onus symbol
t = transit symbol
The check number is the 543123 portion, so when it asks for the check number when designing this check, you should put in whatever check number you entered in for the check number.
If you use temporary checks, then you should make up a number in the MICR line and enter that same number in the check number field.