AX 2012 Error: Cannot create a record in General journal entry (GeneralJournalEntry). Date: . The record already exists.

The above subject is an error message from AX 2012 R3, commonly happening here, even you once solve it again this message will welcome you.
See the message as blow.
Problem:

 Solution:
 Go to xxx/Organization administration/Common/Number sequences/Number sequences (here XXX is your legal Entity name).

find your Number sequence for General journal transfer. 
See below in my case:

 Open this number sequence and edit. Locate Continuous check mark.

 

And  untick this continuous option and then try to post your Journal.
After once posted, you can com here and tick this option same like before which will not affect you for further postings.

Thank you

Have a nice day!!!

Mr. 221