Only one exiftool is used during metadata import

[sampson]

From Windows Task Manager, there are two process of imatch2017x64.exe and 4 exiftool.exe started. 

But only one exiftool.exe is in use (as indicated by cpu usage, three of them always zero)

Is that normal?

How to make iMatch use more exiftool.exe process to speed up the metadata import process?

[Mario]

IMatch always uses multiple ExifTool instances. How much these utilize CPU and other resources depends on the files processed, the disk performance and many other factors. See Process Control in the IMatch help for more information.

Maybe ExifTool is choking on some of your files?
Please switch IMatch to debug logging (Help menu > Support) and then repeat the process. ZIP and attach the log file. This will show us how ExifTool is performing, if it reports any problems etc. See log file in the IMatch help system for full details.