Malbec is already open
Another copy of Malbec is running on this Mac. Use that one, or quit it and try again.
What happened
Only one copy of Malbec can run at a time, because every copy uses the same games and stores. Another one is open, often an older copy in Downloads or on the disk image.
The fix
Switch to the other copy, or quit it, then click Try Again. Keep one Malbec, in Applications.
When to write to us
If no other copy is open and Malbec still says this, write to us.
Email support@malbec.app. For a diagnostics file, choose Help › Export Diagnostics… in Malbec and attach the zip it saves. It has no account details, and your home folder is masked.