Hi there! I’m sorry to hear that Banktivity is stuck on an error screen and won’t open properly on your Mac running OS X 10.15. To help you better, can you tell me if there’s any specific message or code shown on the error screen? Or is it just a general freeze with no details? Also, had Banktivity been working fine before, or did this problem start after any update or change?

In the meantime, here’s a straightforward set of steps to try that can often resolve such startup issues on your Mac:

1. Force Quit and Restart Banktivity
- Use Command + Option + Esc to bring up the Force Quit window. If Banktivity is listed as “Not Responding,” select it and click Force Quit.
- Then, try reopening the app.

2. Bypass macOS Security if You See a Warning About the App Not Being Verified
Sometimes macOS prevents apps from opening if it can’t verify them for security reasons. If you see a message about the app not being checked for malicious software:
- Go to Apple menu > System Preferences > Security & Privacy > General tab.
- At the bottom, you may see a button that says “Open Anyway.” Click that to allow the app to launch.

3. Restart Your Mac
Sometimes a simple restart can clear temporary system states that interfere with app startups.

4. Check for Updates
- Open the Mac App Store and see if there are any updates for Banktivity or your system software. Updating can fix bugs causing the freeze.

If these steps don’t work, there might be an issue with the Banktivity ID or syncing settings. In that case, you can sign out of your Banktivity ID on all devices (Mac and iOS if you use that) and sign back in. Also, resetting or recreating syncing settings sometimes helps.

Let me know how these first steps go or if you see any specific error messages, and we can dig deeper from there!

Are you satisfied with the solution I provided so far?