I am using XP.When I try to fix the problem by running sfs /scannow, I get the message:"Files that are required for windows to run properly must be copied to the DLL cache...insert you windows XP professional service pack 3 cd now"My machine came with XP preinstalled on D: drive. I did make the HP Recovery Disc when I got the machine, but these disc don't work for this and I can't seem to redirect the scan to look on the "D" drive assuming that is the correct thing to do.I have run windows one care and it says I have 150 errors it can't fix. Before these problems started, it never reported more than one error it couldn't fix.

Hi slew999,If you have “ServicePackFiles” folder in C:\Windows (C is the drive where Windows is installed) then, you may try the steps from the following article link and check if it helps:You are prompted to insert a Windows XP SP2 CD when you try to run the System File Checker tool on a Windows XP SP2-based computer(Applicable for Windows XP SP3)If you do not have “ServicePackFiles” folder then, you will have to get in touch with the System Manufacturer for a Windows XP CD.Hope this helps.Thanks and Regards,Santosh Y – Microsoft SupportVisit our Microsoft Answers Feedback Forum and let us know what you think.

Trying to run msconfig you see a message like this:MSConfig.exe - Unable To Locate ComponentThis application failed to start because MFC42u.DLL was not found. Re-installing the application may fix this problem.You can click OK, but msconfig will not open.The problem is that the following file is missing:c:\windows\system32\mfc42u.dllYou will need to search your system and find another copy of the file and copy/paste it into c:\windows\system32.Look here first:c:\window\system32\dllcacheIf you don't see it there, search your hard disk and find one or copy one from a working system to a USB or floppy drive and replace the file. Running sfc /scannow will not help you. It will not replace the missing file - that is not what sfc /scannow is supposed to do. You can learn about how sfc /scannow really works (and what it does NOT do) by booting your system in Safe Mode so that Windows File Protection is not running.For your test, rename the c:\windows\system32\mfc42u.dll file to something you can remember - like c:\windows\system32\mfc42u.tmp.Then run msconfig and you will see the error message about the missing file. The msconfig is now broken (and so is your Event Viewer).Reboot your system in normal mode and run msconfig and you will see that it still will still not work.Run sfc /scannow and let it complete and then run msconfig again and msconfig will still not work because the missing file has not been replaced.When sfc /scannow starts, you will see a message like this in the Event Viewer System log:Event Type: InformationEvent Source: Windows File ProtectionEvent Category: NoneEvent ID: 64016Windows File Protection file scan was started.When sfc /scannow completes and finds nothing to do, you will see a message like this in the Event Viewer System log:Event Type: InformationEvent Source: Windows File ProtectionEvent Category: NoneEvent ID: 64017Description:Windows File Protection file scan completed successfully. Summary:Running sfc /scannow does not replace missing protected files.Running sfc /scannow does not replace corrupted protected files.Running sfc /scannow is often frustrating and generally a waste of time (it is not a file replacer)Running sfc /scannow should never find anything to do (but it feels good when it works).If sfc /scannow ever finds anything to do, you have some other system problem to fix.If you want to run sfc /scannow your need to have an XP installation CD that matches your installed Service Pack (make one if you need one), or you need to tell SFC to look someplace besides the CD you don't have for files. I have never seen sfc /scannow fix anything and will never even suggest it.You can sure run sfc /scannow if you have some time, but you will find that any missing system files will not be replaced. You will also find that your corrupt or suspicious system files will not be replaced. Do, or do not. There is no try.I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!

Trying to run msconfig you see a message like this:MSConfig.exe - Unable To Locate ComponentThis application failed to start because MFC42u.DLL was not found. Re-installing the application may fix this problem.You can click OK, but msconfig will not open.The problem is that the following file is missing:c:\windows\system32\mfc42u.dllYou will need to search your system and find another copy of the file and copy/paste it into c:\windows\system32.Look here first:c:\window\system32\dllcacheIf you don't see it there, search your hard disk and find one or copy one from a working system to a USB or floppy drive and replace the file. Running sfc /scannow will not help you. It will not replace the missing file - that is not what sfc /scannow is supposed to do. You can learn about how sfc /scannow really works (and what it does NOT do) by booting your system in Safe Mode so that Windows File Protection is not running.For your test, rename the c:\windows\system32\mfc42u.dll file to something you can remember - like c:\windows\system32\mfc42u.tmp.Then run msconfig and you will see the error message about the missing file. The msconfig is now broken (and so is your Event Viewer).Reboot your system in normal mode and run msconfig and you will see that it still will still not work.Run sfc /scannow and let it complete and then run msconfig again and msconfig will still not work because the missing file has not been replaced.When sfc /scannow starts, you will see a message like this in the Event Viewer System log:Event Type: InformationEvent Source: Windows File ProtectionEvent Category: NoneEvent ID: 64016Windows File Protection file scan was started.When sfc /scannow completes and finds nothing to do, you will see a message like this in the Event Viewer System log:Event Type: InformationEvent Source: Windows File ProtectionEvent Category: NoneEvent ID: 64017Description:Windows File Protection file scan completed successfully. Summary:Running sfc /scannow does not replace missing protected files.Running sfc /scannow does not replace corrupted protected files.Running sfc /scannow is often frustrating and generally a waste of time.Running sfc /scannow should never find anything to do (but it feels good when it works).If sfc /scannow ever finds anything to do, you have some other system problem to fix.If you want to run sfc /scannow your need to have an XP installation CD that matches your installed Service Pack (make one if you need one), or you need to tell SFC to look someplace besides the CD you don't have for files. I have never seen sfc /scannow fix anything and will never even suggest it.You can sure run sfc /scannow if you have some time, but you will find that any missing system files will not be replaced. You will also find that your corrupt or suspicious system files will not be replaced. Do, or do not. There is no try.I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!

Do you have an i386 folder on your C or D drive and if yes, does it have a file in it called:mfc42u.dl_That would be the compressed version of your missing file which you can uncompress. If you need help with that, let us know. Do, or do not. There is no try.I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!

Trying to run msconfig you see a message like this:MSConfig.exe - Unable To Locate ComponentThis application failed to start because MFC42u.DLL was not found. Re-installing the application may fix this problem.You can click OK, but msconfig will not open.The problem is that the following file is missing:c:\windows\system32\mfc42u.dllYou will need to search your system and find another copy of the file and copy/paste it into c:\windows\system32.Look here first:c:\window\system32\dllcacheIf you don't see it there, search your hard disk and find one or copy one from a working system to a USB or floppy drive and replace the file. Running sfc /scannow will not help you. It will not replace the missing file - that is not what sfc /scannow is supposed to do. You can learn about how sfc /scannow really works (and what it does NOT do) by booting your system in Safe Mode so that Windows File Protection is not running.For your test, rename the c:\windows\system32\mfc42u.dll file to something you can remember - like c:\windows\system32\mfc42u.tmp.Then run msconfig and you will see the error message about the missing file. The msconfig is now broken (and so is your Event Viewer).Reboot your system in normal mode and run msconfig and you will see that it still will still not work.Run sfc /scannow and let it complete and then run msconfig again and msconfig will still not work because the missing file has not been replaced.When sfc /scannow starts, you will see a message like this in the Event Viewer System log:Event Type: InformationEvent Source: Windows File ProtectionEvent Category: NoneEvent ID: 64016Windows File Protection file scan was started.When sfc /scannow completes and finds nothing to do, you will see a message like this in the Event Viewer System log:Event Type: InformationEvent Source: Windows File ProtectionEvent Category: NoneEvent ID: 64017Description:Windows File Protection file scan completed successfully. Summary:Running sfc /scannow does not replace XP protected files that are missing.Running sfc /scannow does not replace XP protected files that are corrupted.Running sfc /scannow is often frustrating and generally a waste of time (it is not a file replacer)Running sfc /scannow should never find anything to do (but it feels good when it works).If sfc /scannow ever finds anything to do, you have some other system problem to fix.If you want to run sfc /scannow your need to have an XP installation CD that matches your installed Service Pack (make one if you need one), or you need to tell SFC to look someplace besides the CD you don't have for files. I have never seen sfc /scannow fix anything and will never even suggest it.You can sure run sfc /scannow if you have some time, but you will find that any missing system files will not be replaced. You will also find that your corrupt or suspicious system files will not be replaced. Do, or do not. There is no try.I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!

Yes, I have a folder c:\windows\i386 and it has the mfc42u.dl_ file, however, when I went to open it, Windows went online and said "file type: unknown"I do not know how to uncompress the file, so if you can help with that, I would appreciate it.

Hi slew999,Try the following methods and check if it helps:Method 1:a. Open "My Computer".b. Browse the location "C:\Windows\System32".c. If you find mfc42u.dll then right click on it and rename it to "mfc42u.old" (without quotes). If you do not find the dll file then, process with the next steps.d. Click Start, click Run and type "cmd" (without quotes) and press enter.e. Type the following command one by one and press enter:· expand C:\Windows\i386\mfc42u.dl_ C:\windows\system32\mfc42u.dll· exitf. Restart the computer and check the status of the issue.Method 2:a. Click Start, click Run, type regedit in the Open box, and then click OK.b. Locate the following registry key:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setupc. In the right pane, right-click ServicePackSourcePath, click Modify, type then following location and click Ok:%windir%\i386d. Now try running sfc /scannow now again.Hope this helps.Thanks and Regards,Santosh Y – Microsoft SupportVisit our Microsoft Answers Feedback Forum and let us know what you think.

Santosh Y has the correct syntax to expand the file. You already have the "expand" program on your system.The files you see out in i386 with the underscore as the last character are compressed files (to save space). This kind of compression is not the same as when you tell XP to compress a file. It is sometimes useful to understand that you can uncompress any of those files out there is you need them if you come across one that is missing or suspicious sometime later. Browse that folder and you will see a lot of compressed files where the last character is an underscore character.Remember - sfc /scannow will not replace missing files and it will not replace a file that may have been overwritten by some other program, but you can always expand a fresh copy.Just be careful to type the commands in perfectly to get it to work.I have my XP Service Pack 3 installation CD copied out to my E drive in a folder called E:\xp_source and when I expanded my mfc42u.dl_ file I got a result like this: C:\>expand e:\xp_source\i386\mfc42u.dl_ c:\windows\system32\mfc42u.dllMicrosoft (R) File Expansion Utility Version 5.1.2600.0Copyright (C) Microsoft Corp 1990-1999. All rights reserved.Expanding e:\xp_source\i386\mfc42u.dl_ to c:\windows\system32\mfc42u.dll .e:\xp_source\i386\mfc42u.dl_: 378327 bytes expanded to 981760 bytes, 159% increase. The new expanded file will not have the current date/time on it, so don't expect to see that - just verify the missing file is now present.It would take some unnatural effort to actually delete one of the 3498 protected XP files like yours. If you rename or just delete one of those files, Windows File Protection will quickly and silently replace it unless it is also broken, so you might want to figure out how your file became missing in the first place. If you manually delete or rename a monitored system file, you will see an event like this in the Event Viewer System log when Windows File Protection replaces it:Event Type: InformationEvent Source: Windows File ProtectionEvent Category: NoneEvent ID: 64002Description:File replacement was attempted on the protected system file c:\windows\system32\mfc42u.dll. This file was restored to the original version to maintain system stability. The file version of the system file is 4.1.0.6151.I would suspect some antivirus or antimalware application quarantied (effectively deleted) your file for you and that would be a problem.Describe your current antivirus and anti malware situation: McAfee, Symantec, Norton, Spybot, AVG, Avira!, MSE, Defender, ZoneAlarm, PC Tools, Comodo, etc.Whatever you are using, you may want to follow up with these:Download, install, update and do a full scan with these free malware detection programs:Malwarebytes (MBAM): http://malwarebytes.org/SUPERAntiSpyware: (SAS): http://www.superantispyware.com/They can be uninstalled later if desired.When the scans run clean, then troubleshoot any remaining issues. Do, or do not. There is no try.I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!

Santosh Y has the correct syntax to expand the file. You already have the "expand" program on your system.The files you see out in i386 with the underscore as the last character are compressed files (to save space). This kind of compression is not the same as when you tell XP to compress a file. It is sometimes useful to understand that you can uncompress any of those files out there is you need them if you come across one that is missing or suspicious sometime later. Browse that folder and you will see a lot of compressed files where the last character is an underscore character.Remember - sfc /scannow will not replace missing files and it will not replace a file that may have been overwritten by some other program, but you can always expand a fresh copy if you ever need to.Just be careful to type the commands in perfectly to get it to work.I have my XP Service Pack 3 installation CD copied out to my E drive in a folder called E:\xp_source and when I expanded my mfc42u.dl_ file I got a result like this: C:\>expand e:\xp_source\i386\mfc42u.dl_ c:\windows\system32\mfc42u.dllMicrosoft (R) File Expansion Utility Version 5.1.2600.0Copyright (C) Microsoft Corp 1990-1999. All rights reserved.Expanding e:\xp_source\i386\mfc42u.dl_ to c:\windows\system32\mfc42u.dll .e:\xp_source\i386\mfc42u.dl_: 378327 bytes expanded to 981760 bytes, 159% increase. The new expanded file will not have the current date/time on it, so don't expect to see that - just verify the missing file is now present.It would take some unnatural effort to actually delete one of the 3498 protected XP files like yours. If you rename or just delete one of those files, Windows File Protection will quickly and silently replace it unless Windows File Protection is also broken, so you might want to figure out how your file became missing in the first place. If you manually delete or rename a monitored system file, you will see an event like this in the Event Viewer System log when Windows File Protection replaces it:Event Type: InformationEvent Source: Windows File ProtectionEvent Category: NoneEvent ID: 64002Description:File replacement was attempted on the protected system file c:\windows\system32\mfc42u.dll. This file was restored to the original version to maintain system stability. The file version of the system file is 4.1.0.6151.I would suspect some antivirus or antimalware application quarantied (effectively deleted) your file for you and that would be a problem.Describe your current antivirus and anti malware situation: McAfee, Symantec, Norton, Spybot, AVG, Avira!, MSE, Defender, ZoneAlarm, PC Tools, Comodo, etc.Whatever you are using, you may want to follow up with these:Download, install, update and do a full scan with these free malware detection programs:Malwarebytes (MBAM): http://malwarebytes.org/SUPERAntiSpyware: (SAS): http://www.superantispyware.com/They can be uninstalled later if desired.When the scans run clean, then troubleshoot any remaining issues.Do, or do not. There is no try.I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!