How to Fix: Internet Explorer Error 9c59 When Updating

Infopackets Reader Tim T. writes:

" Dear Dennis,

My Windows 7 was corrupt and I did a Windows Repair Install to fix it, whereby I used my original Windows 7 DVD (with Service Pack 1) and reinstalled Windows over top of Windows to fix the corrupt system files. After Windows finished installing, it downloaded 230+ updates. Everything went fine except I receive Internet Explorer 10 error 9c59 when updating from Internet Explorer 8. I tried to download the full version of Internet Explorer 11 using the 'offline installer' file to get around this problem, but also received error code 9c59 even when installing Internet Explorer 11. I have searched online for a fix but nothing seems to make it work. Any ideas? "

My response:

I have not had this problem before, so I asked Tim if I could connect to his computer using my remote desktops service to review the problem, and he agreed. In a nutshell, this bug was a real pain to fix, resulting in a lot of trial and error. As such, I'll keep it to a minimum as to how I was able to upgrade Tim's Internet Explorer version 8 to Internet Explorer 11 which is the latest and final version available of Internet Explorer for Windows 7.

How to Fix Internet Explorer Error 9c59

Based on my experience, Internet Explorer error 9c59 appears to be the result of of .NET framework version 4.51 (or in my case, 4.61) conflicting with Internet Explorer and its corresponding language pack install files. I say this because every time I attempted to upgrade to Internet Explorer 11, it would crap out and fail. When it finally worked, the Internet Explorer 11 offline installer made mention of the language pack installing properly -- but only when I uninstalled .NET framework 4.6, first. As such, here are the steps I used to fix Internet Explorer 9c59:

1. As Tim noted, he did a Windows repair install. Although the repair install is designed to fix corrupt system files, his system files were -still- corrupt after the upgrade. To fix this, I checked his C drive for errors, and then ran 'sfc /scannow' using an administrative command prompt. I suggest anyone reading this do the same before proceeding on. To do so: click Start, then go to My Computer, then right click over the C drive and select Properties. Go to the Tools menu, then look for the 'Error checking' heading and click the 'check' button. A new window will appear; ensure that 'Automatically fix file system errors' has a check mark beside it, then click OK.
    
2. Next, open an elevated Windows command prompt. To do so: click Start, then type in "cmd" (no quotes), and wait for CMD.EXE or Command Prompt to appear in the list, then right click it and select 'Run as administrator'. Then, highlight the text below with your mouse:
   
   sfc /scannow
   echo this is a dummy line
    

3. Right click over top of the highlighted text above, then select "Copy". Then, go to the administrative command prompt and right click in the middle of the window and select Paste from the dialogue menu. The 'sfc' or system file checker utility should start running; this will take a while. If there are any errors, hopefully they will be fixed. If you still have errors then you may need to issue another Windows repair, or backup and reinstall Windows from scratch.
    

4. Considering that Tim just did a Windows Repair install, his entire system had to be re-patched; as he noted, all of his updates had to download again (with the exception of the Internet Explorer update, which kept failing with error code 9c59). Since Internet Explorer wasn't updating, it meant that he was still running a very old and outdate Internet Explorer 8 -- which is very dangerous and susceptible to exploits.
   
   From this point I tried downloading Internet Explorer 11 offline installer, then Internet Explorer 10 offline installer (32 bit and 64 bit here) -- but none of those would install -- both with Internet Explorer 9c59 errors. I then tried to download and install Internet Explorer 9 offline installer (32 bit and 64 bit here), and that finally worked; I then had to reboot the machine.
   
   Upon reboot I tried to run the Internet Explorer 11 offline installer again, but it still failed. Then I did some research and found that .NET framework version 4.5x (or higher) may cause the Internet Explorer upgrade to fail. Tim's system had 4.6.1, so I uninstalled that, then rebooted, and then ran the Internet Explorer 11 offline installer again and this time it worked -- and this time, it made mention of installing a language pack during the installation (whereas before it did not), so I knew it was really working. When that was finished, I reinstalled .NET framework 4.6.1 on his system -- because one of his programs required it -- and everything was working 100%.

I sincerely hope this helps anyone else with Internet Explorer error 9c59 -- especially anyone that is doing a Windows Repair install, or upgrading from Home to Pro, or Enterprise (as this would effectively be the same scenario). This was a real pain in the butt to fix, requiring many, many hours to sort through.

Got a Computer Question or Problem? Ask Dennis!

I need more computer questions. If you have a computer question - or even a computer problem that needs fixing - please email me with your question so that I can write more articles like this one. I can't promise I'll respond to all the messages I receive (depending on the volume), but I'll do my best.

About the author: Dennis Faas is the owner and operator of Infopackets.com. With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.