Without knowing the version of Movie Edit pro you have:
In the export preset did you select Surround Sound for the audio format and get a message telling to change the option to Stereo?
If so, you have an older version of Movie Edit Pro for which Surround Sound is no longer supported - this was due to issues with licensing by Dolby and has affected several other video editing programs.
If not then we need more information:
computer specification
the version number of Movie Edit Pro
the format of your imported video
the export preset you are selecting and any changes you made to the default settings of the preset
See this topic for what is required for the above and please quote the processor and graphics card/chipset make/model in full.
. . . . preset. Standard PAL AC3. start export. . . . Download an extensionpackage. . . . .
Hi
Assuming you are trying to export as AC3 Surround Sound 5.1.
This codec is no longer supported in older versions of Movie Edit Pro 2021 and earler due to licensing issues with the codec - this has affected other video editors as well. You should have had the popup shown below advising you the format was not supported and switch the audio to Stereo, this you must do.