IK_Multimedia
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AmpliTube 4 does not require QuickTime so it is no longer an optional component during the install process. For T-RackS, however, it is used for importing MP3 files in the standalone version so if you remove QuickTime on your Windows system you will no longer be able to do so.
Years ago, a developer could pretty much count on the presence of Quicktime on a user's system, Mac or Windows. I'm going to guess that, based on your statement, that the Quicktime method for importing MP3s saved either the licensing cost for an MP3 codec or requiring the user to separately install the LAME codec (which I've done plenty of times, anyway).
If that's the case, hopefully, a simple mod to use the LAME codec could add that capability back, since we know that Quicktime for Windows is gone for good.