Please turn off the “generate thumbnail images” option and the “scan into archives” option in the “Scan” tab of the preferences window.
To shorten the scan time, you can scan required folders in a disk instead of a whole disk.
Did you have the slowdown problem when scanning a NAS drive? Please turn off the “import metadata” option in the “Scan” tab of the preferences window. If your NAS supports both of AFP and SMB network protocols, we recommend you to use AFP instead of SMB. Some NAS products have a performance problem when using SMB on macOS.