If you cannot post to a particular period as you are getting an error ' User 'X' cannot post transactions to period XXX as this is a restricted period' then please see the following:
The user hasn't got permission to post to restricted periods in Dimensions. You will need to check the permission and change / enable this in user security profile.
To locate the user record to determine which Security Profile they are in, click System, User Records
Locate the user and make a note of the Profile.
To locate the Security Profile, click System, Profiles
Find and select the Security Profile using the Binoculars to search for the Security Profile by its name. Alternatively, use the green arrows to search through the Security Profiles
Within the Security Profile, click Periods. Take note of the periods in which this Security Profile is allowed to post up to.
Note: If Working Periods is enabled within Dimensions then this should also be checked to see whether the users can Post to restricted periods.
Within the same Security Profile click Global.
Select the Post to restricted periods check box. This will only show if the option Enable Working Periods is defined in System, Options, System Options, Ledger Defaults.
Click Save and close
Ask the user to log off from Dimensions and log back in order for the changes to be appear.