GanttProject software supports both the import and export of Microsoft Project plans (*.mpp) so you can use that software for GAN to MPP conversion. You can download the program for free.
Convert GanttProject project plan to Microsoft Project plan.
We have found one software suitable in our database for this conversion.
Multiplatform software - convert gan to mpp on any platform
GanttProject is a free cross-platform desktop tool for project scheduling and management available in Windows, Linux and Mac OS X versions.
Convert from gan file
to mpp file
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.