Trying to repair a corrupted Windows 11 - no Internet access

Operating Systems & Open Source Windows
1

Hello everyone!

I’ll start with a TL;DR.

I have a PC with a Windows 11 installation that has corrupted files. Initially I thought this isn’t a big deal, but quickly ran into a snag. Most solutions want to connect to Microsoft Update in order to do the repair. What (I think) is broken are the services related to networking. In other words, I have no Internet access.

Have tried to use DISM in order to repair the files as SFC does not work. Regardless of what I try, DISM also errors out. If I type DISM /online /cleanup-image /restorehealth /source:WIM:E:\sources\install.wim:6 /limitaccess it errors with 0x800f0950. I did verify the packaging format, install media location and index number in the image is correct. Commands were run with elevated privileges.

Are there other methods I can repair the system files with, that doesn’t require Internet access? Am I perhaps approaching the problem with the wrong tools? I am unfamiliar with modern Windows tools and practices.

Here are some more background information:

The computer was put together with new hardware and installed a fresh Windows 11 Pro about one month ago. Have spent many hours customizing and configuring the system to something I’m comfortable with. A few days ago I experienced a crash. The computer froze and rebooted. No error screen appeared. When it came back up, it appeared normal, but were no longer connected to the network.

Troubleshooting this, I noticed it reported a 100 Mbit connection when it should be 2.5 Gbit. The built-in troubleshooter insisted an incompatible static IP is configured, but it is clearly configured for DHCP. Tried different cables and other easy solutions, but eventually found that pin 8 was shorted to the cable shield. I rectified this and found there still was no Internet connection, but at least it recognize there is a 2.5 Gbit link now.

Still puzzled by this, I noticed Windows Firewall complained that it is turned off. I found this strange, as I left those bits of the system configuration as default. Tried to turn it back on, but were greeted with a hexadecimal error code. Doing some other checks, I concluded that everything is configured as it should, but still doesn’t work.

Suspecting that perhaps the system files are damaged, especially those related to the networking part, I ran SFC /scannow as it was the first recommended step when searching around. It recognized there are problems, but could not repair them. Doing some more reading, I learned that if that is the case then DISM is needed to do the repairs needed for SFC to work.

Have tried running DISM with both the image used a month ago, and a new download from Microsoft, but both give the 0x800f0950 error. I even did a checksum verification and found both ISO images to be identical.

I’m including the CBS log file generated, in case it can give someone more knowledgeable some clues. If it is necessary to repeat some steps in order to document the output better, I’m happy to do so. It is very possible I have completely misunderstood something and am currently looking for a red herring with inappropriate tools.

CBS.zip (359.9 KB)

2

Can you download a Windows ISO on another machine and put it on, say, a USB, and point DISM at that ISO?

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3

My roommates windows 11 computer just stopped showing the wifi yesterday and i spent the whole day fiddling with it to no success

4

Find ‘Network Reset’ in Settings, and see if that helps. If not, in the interest of time spent, you should accept defeat, back up your files, and reinstall Windows.

While you’re at it, you might want to try and see if Linux can be used instead.

2 Likes
5

I have tried both the USB stick used for the installation a month ago, and the same ISO copied to another drive as well as a new download from Microsoft.

I’ll have a look. Thank you.

I’ll look for that setting later.

As mentioned, I have spent some time getting things set up. Windows has become less flexible over the years. Couldn’t even move the task bar for some reason now. If I can spend some time trying to repair the installation, I would like to do that. Both because I don’t want to go through looking for the settings again and that I want to learn the recovery process.

I have been a Linux user for many, many years now. This computer contains hardware and software that has to run on Windows.

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6

running sfc /scannow from an admin command window can sometimes help at least identify corrupt files and sometimes fix them.
Reset network , found under Advanced network settings has save me a couple of times.
neither should require network access

7

Network Reset had no effect, unfortunately.

I also ran the following commands with elevated privileges:

netsh winsock reset
netsh int ip reset
ipconfig /release
ipconfig /renew
ipconfig /flushdns

The first one gave no errors, while the second came with a “failed, access denied” error. The latter three all output something like “RPC service unavailable.”

Looking in the logs, there are some indications that my install is newer than the ISO image.

2025-11-20 18:33:32, Info DISM API: PID=3640 TID=5332 DismApi.dll: API Version 10.0.26100.7019 - DismInitializeInternal

The current installation is at 26200, while the ISO appear to be 26100. Probably why DISM fails, as it tries to repair with older files.

Have to dig deeper.

EDIT:
Pulled on the brakes and went back to check some simple things again. Opened services.msc and checked the DHCP service. Found it is set to automatic, but isn’t running. Trying to start it resulted in an “Error 5: Access is denied.” That does explain why there’s no Internet access, but still have to repair the corrupted files somehow.

I also went into regedit and changed all keys named 26 under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nsi\ to “full control” under the permissions. This allowed netsh int ip reset to run successfully. Still no Internet access.

Looks like I have to resort to using an ISO to do the repairs. Found a site called UUP dump that can build an ISO with the latest updates. The catch is that the tool works best on a Windows machine. As mentioned earlier, I’m a Linux user and currently the machine I’m trying to repair is the only Windows computer I have at home. The tool does run on Linux too, but does not add the necessary updates then. Have asked a friend to help out here, but will try to do this at work on a Windows computer there as well.

8

Have you checked the network settings? To make sure that the PC is set to be discoverable on the network.

Network

9

And, on the off chance that some malware made it onto your system, if the offline scan in Windows Security still works, that might be worth a try. Takes about 10 - 45 minutes, but if nothing else, a negative result - nothing found - gives a little peace of mind.

And (again, depending on the level of function remaining), maybe scanning the PC - RAM, CPU and the disk (SSD)- for hardware issues might be worthwhile also. Mem86 can do some of that, and there are other utilities. Windows 11 is certainly no great OS, but if got so corrupted in such a short time that SFC/Scannow won’t even run, the PC’s hardware would be on my list of “the usual suspects”. Probably doesn’t hurt checking that part of the Process of Elimination. And it can be done while you’re getting the reinstall ready.

10

Tried setting a static IP address. The DHCP service is not running, but the network stack itself appear to be fine. Unfortunately it did not bring me online with the computer. Set it using the old method found by running ncpa.cpl. A reboot was performed afterwards, but still nothing. Tried using the modern UI, but it complained that “this setting is managed by your organization” or something like that and didn’t allow me to save it.

Attempted to restore all local security policies to default values by running secedit /configure /cfg C:\Windows\inf\defltbase.inf /db defltbase.sdb /verbose, but that just made the system more unhappy. After a reboot I were greeted with a black screen telling me the device ran into a problem and needs to restart, along with some more hexadecimal error codes.

Got some help to build a new ISO that should contain the files appropriate to my system. Booted into the recovery enviroment. The method is less than elegant, but apparently that’s how it is now. Ran DISM again, but it failed with the same error code as before.

I appreciate your suggestion, Grog. Although I don’t see how it would be relevant, I tried to turn it on. Unfortunately it didn’t cause any noticeable difference. Still no Internet access.

Probably not a dumb suggestion, eastcoastpete. The hardware was bought brand new a month ago, and I am conscious about ESD safety. Although unlikely, I suppose it shouldn’t be ruled out there could be a hardware problem. I do sometimes experience the computer beeps one long and three short when starting, which appear to suggest a graphics card problem. Regardless, it never halts and always display an image.

As for malware, I also find this a bit unlikely but not impossible. The computer is used for specific tasks. If I surf the web with it, I visit trusted websites. Firewall and Defender were left on default settings as I had no need to tinker with those. Judging by how much support wheels the system in general has, I would be surprised if default settings wouldn’t be sufficient. Especially since it is being kept up to date.

I’ll try to run some additional diagnostics.

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11

I just thought it was worth checking (the basics). As I had a similar issue with a recent Windows install that had no internet access. I initially thought it was a faulty ethernet port. But turned out to be that.

12

Interesting! Seemingly unrelated things do sometimes have relation with each other.

13

The Windows repair utility Tweaking may be of some help then. Here is a link to the official website: https://www.tweaking.com/

MajorGeeks also host a mirror, & have a good description of what it does. Link: Download Tweaking.com - Windows Repair - MajorGeeks

14

It is a good suggestion, but reading on what it does I don’t think it is applicable to my situation. This isn’t a configuration or permission issue. There are clear signs of corrupted files which breaks some system services.

I have tried to reset various configs and permissions through PowerShell and Registry Edit and have run into errors multiple times. Doing changes may cause errors to pop up or have no effect due to problems elsewhere. The DHCP service does not start eventhough configured to do so and will not turn on manually for example.

Trying to set a manual IP that is valid does not work. Security policies prohibit it. Trying to default the security policies does not work. It made the system more broken. I’ve also run into a situation where the admin account wasn’t allowed to make a change because only the admin can make the changes.

I have to repair the broken files, but Microsoft hasn’t made that part easy without a working Internet connection. Tried to make a custom ISO with the updates applied, but there are still some problems. Might have missed something that still causes a version mismatch. Worst case the affected files have to be replaced manually, but would be nice to get a script or utility going that can locate and do it automatically.

It is a bit annoying, but the process has been an interesting learning experience. Want to get to the bottom of it out of principle now.

15

Ran MemTest86 while waiting for some deeper analysis of the system logs.

The memory test, to my surprise, failed prematurely because it reached 10.000 errors within a couple of minutes. Appears to have a bit flip as bit 0 is the opposite of the expected value.

Pulled out and inserted each stick. Test fail again as a pair. Checked the manual for which slot to use with a single stick and tested both individually. Both passed. Inserted the second stick, now in the opposite slot of where it was originally. Test pass as a pair now. A bit strange, but I suppose it is fine for now.

Back to focusing on repairing Windows again.

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16

Glad for the update.

If you have already created a bootable Win11 USB stick, & tried to repair the OS with that. (There should be an option to repair the OS, opposed to reinstalling it). My next step would be to perform a clean install of Windows on another drive. (Or backup/clone your existing one). This would at least rule out a hardware related issue.

For good measure, you may want to update the BIOS, & reset it to factory defaults.