There are several websites that offer free downloads of the Umax Astra 5800 scanner driver. Here are a few reliable sources:
Best for users who scan infrequently and don't want to hack system files. Umax Astra 5800 Scanner Driver Free Download
Only download from GitHub (enthusiast repositories), The Internet Archive, or VueScan directly. Never run .exe files from generic "driver download" websites. There are several websites that offer free downloads
Connect the scanner, open Device Manager , right-click the unidentified device, and choose "Update Driver." Manually select "Imaging devices" and then "USB scanner device" (Generic Microsoft driver) to see if basic functionality is restored. The Internet Archive