Did you ever waste time thinking you had a problem in one area, only to find it was caused by something that was easily corrected? That happened to me yesterday, in trying to access the Internet from Tsinghua University School of Law.
Internet access here at the law school has several unusual aspects. In the first place, free wireless service is available in the library and in many classrooms. However, such service permits access only to Chinese-based web sites, plus limited English web sites (namely Google). People who want unlimited Internet access must subscribe to a paid Tsinghua network service called TUNet, and receive a user-ID and password. Furthermore, in order to use TUNet, one HAS to be connected via a physical Ethernet cable connection (i.e., one has to have a cable connection from the computer to a wall jack). TUNet access is not available using a wireless connection (don't ask me why, that's just the way it is--something I have come to expect while here).
I use TUNet on my own laptop, via an installation program my host student, Cissy, gave me. It works fine and I can access the Internet without problems. However, yesterday I did have problems, when using a library computer.
The library in the law school has a computer lab. The computers are connected to a local area network via Ethernet cables. These computers have the same TUNet program, and users can access the Internet.
I went to the lab, sat down by one of the computers, brought up TUNet and tried to sign on. I entered a userID and my password, but was unsuccessful. TUNet displayed a message saying that the password was invalid. I tried several times more, each time getting the same message. I then hooked my own laptop, started TUNet and entered the same password I used for the lab computers. This time, as I expected, I was able to start TUNet just fine. So, I went BACK to the lab computer, started TUNet there, and again I got the same message, "invalid password."
Finally, I went to the TUNet office, and explained to them what was happening. The woman in charge, who has helped me before, asked to sign onto TUNet using a computer in their office, and I did so. Right after I entered a userID and password, she stopped me, immediately noticing an issue. Instead of ending my user ID with "c08" I was ending it with "c2008." I never noticed the issue because my userID is saved on my laptop version of the program. Once I corrected the userID, everything was fine.
Clearly, I made a mistake in entering the userID. The password really had nothing to do with the problem. In both cases, whether on the library computer or on my own laptop, I entered the "right" one. However, when I entered the "wrong" userID, the system couldn't make a match, and gave me an error.
However, think about this situation more: really, the system gave me the wrong message. Chances are, the "wrong" userID I entered doesn't really exist on the system. In that case, rather than telling me "invalid password," it should have told me "invalid userID." That would have saved me time, and kept me from looking in the wrong place for an answer.
Moral: if you're getting error messages, check everything. Don't assume the message is pointing you to the right place. Second, if you're designing a system, make sure your error messages are accurate and not misleading.