I assume you are running a desktop or private server version of Manager.
In which case Manager has been running only on your hardware and not sharing your data with any other computer. That’s excellent for privacy but the flip side is no one else can retrieve your data if lost.
So the answer to your question is you have no choice but to recover your accounting records from the information you alone have.
- your backups
- Your original input data
- Your hard copy of reports
- Your bank feeds