- TWAIN scanners are failing to redirect and not being listed at Connection Properties > Scanning > TWAIN.
- To fix this, one needs to launch Parallels Client as Administrator.
- Procmon capture (gathered after reproducing the issue) contains the following entries:
OS misconfiguration. Either environment variables are missing or an outdated twain_32.dll file prevents Parallels Client from successful operation.
1. Make sure that environment variables set correctly at Control Panel > System > Change settings > Advanced > Environment Variables
Path for TEMP and TMP must be set correctly (as shown on the screenshot below):
2. Check that there is no twain_32.dll file in C:\WINDOWS\SYSWOW64 directory. If the file persists there, delete it.