View Full Version : "Failed to find Steam" and "Missing or invalid authentication key" - SOLVED on XP?

01-03-2012, 03:36 PM
Various threads have talked about problems running Nexus, related to error messages that say:

"Failed to find Steam"
"Missing or invalid authentication key"

For example, these threads:


I encountered both these problems recently. The "solutions" discussed in the above threads did not work for me, but they did help me find the following solution. I am running Windows XP SP2, but the general principles may apply to other systems as well.

Requirement 1 - Nexus must be *installed* as an Admin user.

If Nexus is not so installed, the install will appear to succeed, but no authentication key will be installed in the Windows registry.

Requirement 2 - One of the following must be true:

2a) Steam must be installed in "C:\Program Files\Steam", or

2b) The directory that contains steam.exe must be in the PATH of the admin user who is installing Nexus.

If neither Requirement 2a nor 2b is met, the install will appear to succeed, but Nexus, when run, will not be able to find steam.exe.

(Note: I am guessing that 2a leads to success based on comments in one of the above threads. On my system, Steam is NOT installed in "C:\Program Files\Steam", so I have not personally tested that 2a leads to success.)

So, if you are encountering either of the above problems, try the following:

1) Uninstall Nexus
2) Log in as a user with admin privileges
3) Ensure that the directory that contains steam.exe is included in your PATH
4) Re-install Nexus

After you do the above, Nexus should run, even as a non-admin user, and even if steam.exe is no longer in your PATH.

Good luck!

03-31-2012, 04:52 PM
I want my money back

07-21-2012, 01:55 PM
I made a thread with a solution for "Failed to find Steam" for Win 7 here. (http://forums.steampowered.com/forums/showthread.php?t=2828058) It might be helpful?