I'm trying to change my cash account in the AR Control accounts and it won't let me save the selection. What's the problem?

This is one of Steve Schwartz's favourite questions so I'll answer it for him.

When you open the Control Accounts screen, do you see a message "Warning. Changes cannot be saved until you print and clear all posting journals. Do you want to continue?"?

If so, print & clear the Posting Journals first, then make the change.

Steve has pointed out several times that he would like to see this restriction removed on the grounds that it isn't necessary. However, until that happens, you must follow the rules!

Alright.

This is Steve

The workaround is to rename (temporarily) the files that start ARPOST*.xxx to ARPOST*.yyy, then when you are done making the change, copy the ARPOST*.yyy files back to ARPOST*.xxx (don't rename, rather copy).

Good point - Proof that you don't have to always follow the rules!

Hmmm I am having this problem with 8.1A (070920)
Tried Steve's fix but still get the Warning.
No batches open. No posting journals to print. The cash journal displays posting sequence numbers but when I click print, it says no journal found to print.
Data integrity check clean.

If you have ACCPAC Plus AR lying around, point it at this data and try it using Plus. Adagio is smarter than Plus, and harder to fool with my workaround.