Can I make adding/updating pictures a background process?

[kirk]

I recall there is a setting in preferences or something  that allows to continue woking with imatch while it ads/updates pictures. Seems I forgot whre it is and the Preference dialog looks like a deep dark forest for me now.    I want to add 5TB external usb disk  and it takes days . Would like to be able to work with iMatch meanwhile

[Mario]

IMatch by default ingests (adding new files, updating existing files which have been changed externally) files in the background, unless more than 200 files need to be imported. Then it uses the import overlay to speed up things (you can dismiss this dialog to continue working). See Load Progress Dialog

Write-backs are performed by default on-demand, when you run the write-back command from the Commands menu or you click the pen icon in the file window.
Since this is a demanding operation which constantly invalidates what IMatch has to show you (think: categories, file window contents, collections) IMatch displays a progress dialog while the write-back is performed.

You can switch IMatch to immediately write-back changes in the background. But this has some side-effects you may want to consider.

All options which control IMatch does background processing are accessible via Edit > Preferences > Background Processing. Click <F1> while on this tab to open the corresponding help topic Background Processing

Why does this take days? Are there hundreds of thousands of files to process or is the disk so slow?
CHECK: Make sure you have background write-back disabled under Edit > Preferences > Background Processing. If enabled this can reduce ingesting speed by 60%.