I have a fujitsu scanner. When I do a scan using the Twain driver, MIO.Acquire returns true. When I use the WIA driver, it returns false. I traced the code and when it goes to check "= S_OK", the value is 200k+.
I will have to debug next week (maybe tomorrow). Based upon the value, I am wondering in hindsight if it was the scan size value it was returning, about 250k, which was then being compared to S_OK.