Both the .icontrainer and .icns are fairy common icon libraries and as such support in most available icon handling or editing programs like the IconWorkshop or IconBox. It should be possible to export or save one to another.
Convert Icon container library file to Apple icon graphic format.
We found 2 software records in the database related to .icontainer to .icns file format conversion.
Microsoft Windows software - convert icontainer to icns on Windows
A cross-platform icon making software
Convert from icontainer file format
|Yes, Axialis IconWorkshop supports icns file conversion as a target file type.||Yes||Yes||icns editor||Yes||Yes||Yes||No|
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 icontainer to icns. 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 icontainer to icns on OS X
A great icon organizer and tool for Mac OS X