The ability to save MATLAB 6.5.x (R13.x) GUIs in MATLAB 6.1 (R12.1) format is not available in MATLAB.
As a workaround, you can export the GUI in MATLAB 6.5.x (R13.x) to a single MATLAB program file, then run the exported file in MATLAB 6.x (R12.x). Perform the following steps to export the GUI to a single file:
1. Open the .fig file in GUIDE in MATLAB 6.5.x (R13.x)
2. Go to Tools --> GUI Options. Check the radio button for "Generate Fig-file and MATLAB file". Make sure the three check boxes below the radio button are also checked. Click "OK"
3. Go to File --> Export..
4. Enter the file name and click Save.
You should be able to run the exported file in MATLAB 6.x (R12.x.)
Note that you still may receive errors when running the GUI in MATLAB 6.x (R12.x) since there are several features in MATLAB 6.5.x (R13.x) that were not available in previous versions. For more information on features that are available in MATLAB 6.x (R12.x) and MATLAB 6.5.x (R13.x), access the release notes at the following URL:
People using MATLAB 5.3.1 (11.1) or earlier may experience different issues in running these GUIs. If you would like more information on how to convert a GUI created in MATLAB 6.5.1 (R13SP1) so that it works in MATLAB 5.3.1 (11.1) and earlier versions, see the Related Solution.
