I am having this issue too. I have since disabled the functions.php file in my theme to see if that helps…
This has been an issue with many revisions of WordPress, but there’s no sign of a fix yet.
The root cause is that WordPress reverts to default in certain cases where it cannot find the theme. A lot of conditions are known to cause this to happen falsely. For example, if the filesystem is slightly flaky, then there are instances where it may return an error incorrectly, causing WordPress to reset to default. Another case is where somebody accesses the site at the exact moment you’re uploading a modified version of the theme.
In general, on a normal setup, this problem does not occur. If it is occurring without provocation, then it’s most likely a symptom of other things going wrong on your server. You may want to examine the server in more detail, or warn your host that there may be a bad disk or something along those lines.
Currently, there is no fix for this problem from the WordPress side of things, because it’s not necessarily an issue with the WordPress code. WordPress is doing what it was designed to do. What’s happening is that WordPress is getting false error codes and responding to them in unexpected ways.
I am not necessarily disagreeing with you, Otto, but it only started happening immediately upon my upgrade. This seems a bit more than coincidence. Can you tell me what I might look for on the server side? None of the other WP installs on my box (all still 2.1x and 2.0x, since I don’t want to upgrade while this is a possible issue) are having this problem…
I can’t tell you much about the cause, however I can point you to the known bug ticket about it:
http://trac.wordpress.org/ticket/3907
The short of it is that if the file_exists call fails, it reverts. Whatever you can think of that might cause that call to fail temporarily, I’d look at that.
Just wanted to post back to say that I have found a workaround for this problem. I have renamed my custom theme & folder “default”. Now when wordpress reverts, it at least it reverts to my custom theme!
Tmuka – good idea! I may have to do that, because no matter what I do, server-side or plugin-wise or anything, it hasn’t fixed the problem.
Otto42 – thank you for the input. I haven’t the time or resources to completely overhaul my server, however. I have to say that, while I will continue to use WordPress because it is superior to everything else out there, I cannot help but be confused by the assertion that it is not WordPress’ problem. If I drove a car which, whenever I was in an accident, forcibly changed the clothes I was wearing, I would find that to be a problem with the car no matter who caused the accident. How can the resetting to default of a theme be a proper reaction to any server error?
Kristin
I guess what I am trying to say is, is not the theme you pick in your “Presentation” area your default? Why should it revert to anything but that default? Certainly the server is not telling WP explicitly to change its theme…
