Audacity projects (.aup) can be created only in Audacity and no other software. You can import and work with various audio files in the program (including .aiff audio) and save your work progress a project that references to the audio files, but usually does not contain any audio data them self.
Convert Audio Interchange File Format to Audacity project.
We found 3 software records in the database related to .aiff to .aup file format conversion.
Microsoft Windows software - convert aiff to aup on Windows
A free, open source software for recording and editing sounds
Convert from aiff file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned aiff to aup. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert aiff to aup on OS X
A multi-track audio editing tool
Linux/Unix software - convert aiff to aup on Linux
Multi-track audio editor for Linux