“The language you selected isn’t included in your license key”
When trying to switch the language from English to another in a multilingual version of Foxit PDF Editor, the error above will appear. This is due to the key file left over from the previous version that does not recognize the switched language.
To solve this problem, please locate and delete the key file “fpmkey.txt” under the main installation folder of the Foxit PDF Editor directory below:
C:\Program Files (x86)\Foxit Software\Foxit PDF Editor
Then you will be able to switch Foxit PDF Editor UI language to another one as long as you delete the key file from the main directory.