Hello James,
AxCrypt encrypted files should have a file extension “.axx”. Also, default application for the file type “.axx” should be AxCrypt app only.
If the AxCrypt app is not configured as a default app for the file extension or no other apps are mapped to the file extension.
Might be, the default application is not mapped for the file extension “.axx” in your system. So please change the default application to AxCrypt for the file extension for “.axx” with the help of following links,
https://support.microsoft.com/en-us/help/4028161/windows-10-change-default-programs or https://support.microsoft.com/en-us/help/18539/windows-7-change-default-programs.
You have using the AxCrypt portable version in your system. Please use the installer version.
Download the latest version 2.1.1598.0 of the AxCrypt app(installer version—AxCrypt-2-setup.exe file from our official website (https://forum.axcrypt.net/download/ ).
Still, if you are facing any issues, please write to Support@axcrypt.net. we are happy to help you.