Please avoid sending a same query in different mediums. You may get duplicate response
The error message indicates that the file simply is not an AxCrypt file – it checks the first 16 bytes for a unique value.
This might be happened, because of you are trying to open/decrypt the AxCrypt secure deleted files. Those files will not be recoverable.
Most often, this error occurs because the file is not produced by AxCrypt. It can also happen when users mistakenly rename non-AxCrypt files to end with .axx, in which case renaming back to it’s appropriate extension will fix the issue since the file was never encrypted in the first place in this scenario.
Another scenario is that it is a left-over after a previous decryption was interrupted at the stage where the original is overwritten. The most common reason for this happening is that the file was damaged because of early removal of a USB drive, or a disconnected network drive.
If the file is actually damaged to this extent, no, it can’t be fixed. The data is just not there to decrypt it.
But we have a feature called Try Broken File. You can able to decrypt the corrupted AxCrypt encrypted files by navigating the menu File | Options | enable Debug from the AxCrypt app.
Now you can able to see the Debug the menu in the AxCrypt app. From the debug menu you have to select Try Broken File.
Now you will be prompted for file selection. Select the corrupted encrypted file and then AxCrypt will try to decrypt the file. If successfully decrypted, then you are able to see the decrypted file in the location. Otherwise sorry to say, AxCrypt can’t decrypt that file.