Xp hangs at mup.sys on startup

Question

MY DESKTOP HANGS AT MUP.SYS ON STARTUP.  ANY IDEAS ON WHAT'S CAUSING IT?

Answer 1

I Think what AreilMT is getting at with the HDD light flashing is this:

If you have a chkdsk scheduled to run on the next reboot (by responding in the affirmative to the question when choosing to run a chkdsk on the next reboot), or if XP finds that any volume on your system that has been marked "dirty", chkdsk is going to run when you reboot.

If you boot in Safe Mode and chkdsk starts to run, the last thing you will see on the screen is mup.sys having been loaded...  then the chkdsk is going to run to completion.  Your system will appear to be stuck.

If the system appears to be hung on mup.sys and the HDD light is flashing, it could be that chkdsk is doing what it is supposed to do or what you told it to do - checking the volume(s) for consistency.  If that is the case and the HDD light is flashing, you need to wait it out and that could take many/several hours depending on the size of your HDD, how much stuff is on it and what chkdsk finds to do.  Let it sit overnight if you have to, but be patient.

If that is NOT the case, then I suggest you power off, unplug everything except the keyboard and see if you can boot in Safe Mode with only a keyboard attached.  If you have a PS/2 keyboard to use, I would use that instead of a USB keyboard.  Sometimes a faulty USB device or driver can cause the system to appear to hang on mup.sys.

It is also important to realize that the problem is not with mup.sys (it has already loaded) - it is what comes after mup.sys that could be the problem (if it is not running chkdsk).

This is why it makes zero sense when people see this scenario and start trying to figure out how to replace mup.sys - that is not the problem since it has already loaded. 

The next thing to load that sometimes causes problems is often keyboard and mouse drivers - especially USB keyboards and mouses (mice) devices, hence, you should unplug everything - especially USB devices.  You only need a keyboard connected to press F8 to get to the Advanced Boot Options menu and choose Safe Mode and a PS/2 keyboard should be used if you can get your hands on one.

Answer 2

What are you talking about?

If the system is hanging on mup.sys, the OP is trying to booting in Safe Mode or they would not know that is where is is hanging.

If the system is hanging on mup.sys,  there is no way to continue with your other methods and links.

Have you ever seen this issue before or are you just throwing out some wild guesses?

Answer 3

@Joselbarra: Heh, it's a response as uselessly canned as Microsoft's telephone support.  I wouldn't be surprised if that's his day job, really.

@ROBERTSALSBURY: Does your hard disk activity light show any activity after loading mup.sys?  Also, as canned and utterly useless as Bikesh T's reply is to your situation, there is a good question in there: Did anything significant happen shortly before your PC started booting in Safe Mode, such as installing a new program, making changes to system settings, or encountering strange behaviors/error messages?

Answer 4

Hi,

• What were the changes made before the issue occur?
• How long have you been facing this issue?

You may refer these methods:

Method 1:

Check if the issue exists in Safe Mode, if the computer works as expected in safe mode then we can troubleshoot the issue in clean boot state.

a. Refer to the article below for safe mode steps in Windows XP

A description of the Safe Mode Boot options in Windows XPhttp://support.microsoft.com/kb/315222

b. It is a possibility that there is a startup program that is started with a command line and it shows up.

You are required to perform a clean boot to find the program that is causing this and then disable or remove it.

How to configure Windows XP to start in a "clean boot" statehttp://support.microsoft.com/kb/310353/en-us

Note: After you have finished troubleshooting, follow the steps as explained in the article to reset the computer to start as usual.

Method 2:

You may also perform disk error checking to troubleshoot this issue.

Here is the link:

http://support.microsoft.com/kb/315265

Chkdsk disclaimer.

Important: While performing chkdsk on the hard drive if any bad sectors are found on the hard drive when chkdsk tries to repair that sector if any data available on that might be lost

Also refer:

http://support.microsoft.com/kb/945658

Answer 5

THANK YOU SO MUCH, A. USER!!!!!!!!!!!!!!!!!!!!!!!!!  Your reply above saved me, for real.  Have a wonderful rest of your year; thank you thank you thank you!  I hope many great things happen to you and for you!!!!!!!!!!!!!

-RC

Miami