Scansnap ^new^ Downloads -
Check out VueScan by Hamrick Software. It supports ancient S300 models that PFU abandoned years ago. It isn't free, but it is cheaper than a new scanner. Have a specific error code? Drop it in the comments and I will troubleshoot it for you.
Where do you get the software? How do you avoid the fake "driver download" ads on Google? And why does your new Mac not recognize your scanner? scansnap downloads
Let's walk through the safe, fast way to get your ScanSnap back up and running. If you Google "ScanSnap download," the first three or four results are often third-party driver repositories. Do not use these. Check out VueScan by Hamrick Software