I ran into this error earlier today while attempting to reinstall the WAAE 11.3.6 client on Windows.
This error is thrown by the WAAE installer (InstallShield) while attempting to upgrade or uninstall (e.g. via Add/Remove Programs) the existing installation.
As far as I know, a definitive root cause for this error has never been found.
I have seen cases in the past where a simple reboot of the machine will clear the error. Not today, however.
I was able to successfully clear the error on two separate machines by making an attempt to uninstall CSAM via Add/Remove Programs (appwiz.cpl). In my case this was a separate line item in the installed Programs list. The CSAM uninstall will abort due to the existing dependency from the WAAE client but once the CSAM installer quit the _CaUser error condition was cleared.
Hope this helps someone else.
"As I hurtled through space, one thought kept crossing my mind - every part of the rocket was supplied by the lowest bidder." - John Glenn
All cases, I worked on, wherein customer reported "Unable to load _CaUser." error was resolved by installing the latest VC++ 2010 Redistributable (x86) from the MS site.
When we ran the install after enabling MSI debug (Create subkey Reg_SZ "Logging" with value "voicewarmupx" under key HKLM\Software\Policies\Microsoft\Windows\Installer in the Windows Registry), it appeared to fail during the VC++ 2010 Redistributable installation. After installing the latest VC++ 2010 redist from the aforementioned MS portal, the WAAE 11.3.6 client installation went well.
Please give it a go in case you run into same problem again.
"Unable to load _CaUser" , got same error, even though VC++ 2013 Redistributable (x86) is there on windows 10 machine.
AE does not use VC++ 2013. You need the latest VC++ 2010 Redistributable (x86) from the Microsoft.
Thanks Chandru. Good to know. Updating the VC Redist is not part of the change requests but I may build that in to future requests.