Vuescan? Forget it!
Let this be a lesson to would-be VueScan buyers.
I purchased Vuescan standard edition in 2007 ($40) and upgraded within the year allowed. But the update caused Vuescan to behave unpredictably and often crash my Mac running OS X / 10.4.11. After struggling (and numerous hours invested) I finally sent a detailed description of the problem to Hamrick, as he asked. Without diagnosing the problem, Hamrick suggested I download the latest version - 8.4.85.
Problem solved; works fine again. But now Hamrick is charging me ANOTHER $40, refusing to allow me to use the remedy version without the watermark on every scan in the trial version. Hamrick wants another $40 to upgrade to the professional version.
I've already paid $40 once, and won't pay it again. I first asked to go back to the earliest version that I downloaded and forget about the upgrade. Nothing doing, he said archived older versions would take "hundreds of megabytes" he said. AND HE'S THE DEVELOPER!
Let this be a lesson: When you deal with an individual developer as opposed to a corporation (such as LaserSoft and it's Silverfast scanning software), they are free to dismiss your claims and turn their back. For my $40 invested in VueScan I can only use the trial version now.
Buyer beware. Try Silverfast.