You can use the Standard or Professional Edition of VueScan on up to four different computers that you personally own, with any combination of operating systems, with any number of scanners, both x32 and x64, with a single license.
If more than one person (who isn’t a family member) uses the computer, then you need a separate VueScan license for each computer.
You can use the Basic Edition of VueScan on 1 computer.
You must purchase a separate license for each computer that VueScan is used on. There are discounts available for bulk licenses.
For both personal and commercial use, VueScan licenses are not transferable if you buy or sell your computer.