Kristian,
I am running Photo Mechanic version 4.5.4 and I run Mac OS X 10.5.8 on my Intel-based Mac ;-)
Is it possible to tag multiple photos in the browser window? Fx: I would like to tag 200 photos with the same color.
Yes. Hold down the Modifier key (Option on Mac, Shift on Windows) while you choose the color class on a selected photo and all selected photos will get the same color class.
Or, if like me you enter the colour code/rating using the number keys on the keyboard, simply select the files and then press the corresponding key combination (e.g., CMD-5 to set colour code 5).
Hope this helps,
Hayo