I'm running AxCrypt 1.7.2126.0 64-bit on Windows 7 Home Premium 64-bit and seem to have discovered a problematic interaction between AxCrypt and UAC. To reduce this to as simple as case as possible, I've created the following 2-line BAT file:
start "" "C:\Program Files (x86)\Neutron\Neutron.exe"
"C:\Program Files\Axantum\AxCrypt\AxCrypt.exe" -d d:\Temp\test-txt.axx
Neutron is an application for synchronizing system time with internet time servers.available at http://keir.net/neutron.html, but I don't think the specific application is relevant. What I believe to be relevant is that the application has to be run as an administrator to perform its time adjustment function and therefore produces a UAC prompt if UAC is active.
The other necessary condition for the problem to occur is for AxCrypt to not have a resident passphrase. Let's assume that AxCrypt is being invoked for the first time since a system boot.
When the above shown BAT file is executed, the invocation of Neutron will cause a UAC prompt. In the scenario being described, "Yes" will be clicked to allow Neutron to run. Since Neutron was invoked via a Start command, it remains active as AxCrypt decryption is attempted, but instead of getting the expected request for a passphrase, I get “Internal error in (null). Please report.”.
As best I can tell, the following conditions are necessary to produce this result:
1.AxCrypt must not have a relevant, resident, cached passphrase.
2. An application must be being run as administrator which causes a UAC prompt.
3. Said application and an AxCrypt command must be invoked within a BAT file or other type of script.
4. Interaction with UAC must allow program being run as administrator to execute.
5. Said program must still be active when AxCrypt command runs.