Last year Fujitsu stopped supporting the previous generation document scanners in the 64bit software required in Mac OS Catalina (10.15) and later.
This was very upsetting for many users who’s older scanner was serving them well. If you recently bought a new Mac or installed Mac OS Catalina on your current Mac. You were unable to use the previous generation scanner. This was disappointing, especially since there is no good 3rd party application available for this otherwise excellent document scanner.
The disappointment in the Mac community of loyal Scansnap users was so great that we started looking for alternative document scanners. Thankfully Fujitsu has reversed its course and has updated the ScanSnap Manager V7 to support the earlier models S1500, S1500M, and the S1300.
Link to the download page:
You can find the software for the older scanners at the bottom of this page under the Discontinued scanners section.
Link to Fujitsu announcement page