"This security is in use" when trying to delete a security
You’ll see this message if you try to delete a security that’s still tied to one or more transactions in your investment accounts.
Why you can't delete the security
Quicken prevents you from deleting a security that is:
Referenced in any account register
Part of past or current transactions (such as buys, sells, reinvestments, or transfers)
This ensures your investment history and reporting remain accurate.
How to remove the security
To delete the security:
Open the investment account(s) where the security appears.
Locate and delete all transactions involving the security.
Return to the Security List.
Try deleting the security again.
Once all related transactions are removed, Quicken will allow you to delete the security.