Backup file created by Sage 50, accounting software used to organize financial data; contains an exact copy of the company data.
To create the PTB file, select File → Back Up, choose your settings, and click "Back Up". Then name the file, choose the save location, and click Save.
To restore the PTB file, select File → Restore, follow the appropriate prompts, and finally, click Finish.
You can also restore a PTB file by renaming the extension from "ptb" to "zip" since PTB are compressed with Zip compression. You can then decompress the file and copy the data from the PTB file into the appropriate subdirectory.
NOTE: Sage 50 used to be known as Peachtree Accounting.