The Mac App store is currently having some sort of security issue that is affecting some users who purchased the App Store version of MoneyWork Cashbook (and also many other apps). Affected users get the message long the lines of: “Your software was purchased on another computer, enter your Apple ID”, or “Your software is damaged, please delete and re-download from the Apple store”. Neither of the suggested actions actually appear to fix the issue.
This is an Apple problem, and not something that we can resolve. It appears that a required security certificate was not updated, as reported in The Guardian.
We do not know how long it will take Apple to fix this.
What we will do though is offer all affected users an upgrade to the current full desktop version (MoneyWorks Cashbook 7) for the difference in what was paid for the App Store product and the current retail price ($US99.00). If you wish to take advantage of this please email a copy of your App Store receipt for MoneyWorks Cashbook to firstname.lastname@example.org.
Note: MoneyWorks Cashbook 7 will open your existing Cashbook 6 files (it keeps of copy of the old file and makes a new file in MoneyWorks 7 format, preserving your data).