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Windows 8.1 "class not recognised" errors when opening programs

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Found 25th Oct 2013
Having a real nightmare of a time with Windows 8.1 right now. Tried opening up Cubase 5 and it closed without starting. So I opened Chrome to ask Google what the problem was and it wouldn't open, saying "Class not recognised". Loads of other programs will fail to start either with the "close the program/ask Microsoft for a solution" or the "class not recognised" error. I've tried uninstalling some programs - Control Panel is bugging out and not opening anything in the category view (but will in the icon mode view). Some programs which show up in Uninstall programs think that they've already been uninstalled when they're there. When I've uninstalled (natively) and then reinstalled, the problem of "class not recognised" persists!!

HUKD, you're a brainy bunch, a little help here? I find a few topics on Chrome's problems but this seems to be an OS-wide fault... Short of refreshing my PC back to the beginning, I'm all out of ideas :C
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6 Comments
It was on the news the other day about the number of people who are having the same issues with Windows 8.1 - most folks seems to have to refresh PC back to the beginning - probably not what you want to hear
Is the error message "Class not registered" rather than "class not recognised"? The issue is usually a DLL file which runs as a COM object (COM is an MS technology that provides interface for calling applications into an object from other applications that conforms to the correct standards). Usually the offending DLL (or perhaps OCX) file can be registered via a regsvr32 call. Do you have the full error message that may reveal more information? The message "class not registered" is too generic, since there are many COM objects that are installed within the system. Usually, you will be given a class id or the name of the file that is affected. If you can provide this information, I may be able to provide details on how to register the files.


Edited by: "ElliottC" 26th Oct 2013
Original Poster
ElliottC

Is the error message "Class not registered" rather than "class not … Is the error message "Class not registered" rather than "class not recognised"? The issue is usually a DLL file which runs as a COM object (COM is an MS technology that provides interface for calling applications into an object from other applications that conforms to the correct standards). Usually the offending DLL (or perhaps OCX) file can be registered via a regsvr32 call. Do you have the full error message that may reveal more information? The message "class not registered" is too generic, since there are many COM objects that are installed within the system. Usually, you will be given a class id or the name of the file that is affected. If you can provide this information, I may be able to provide details on how to register the files.



Thanks for taking the time to write this. That's all there was to it, no code to identify the exact problem, just "class not registered" in a non-descript dialog box. The odd thing is that Chrome wouldn't open using the taskbar icon but would from it's location in Program Files. Other programs just wouldn't open at all. I think my Windows 8.1 update did a number on my registry as solutions to the fault usually requires deleting entries in RegEdit.

Luckily I keep all my data backed up so last night I refreshed and reinstalled everything, updating Windows before any software went on. My only worry is that this problem didn't come up straight away - I installed 8.1 on Monday and problems showed on Friday...
Original Poster
Obidashi

It was on the news the other day about the number of people who are … It was on the news the other day about the number of people who are having the same issues with Windows 8.1 - most folks seems to have to refresh PC back to the beginning - probably not what you want to hear



Thank you also for responding - I did refresh in the end and I'm back to a fully working PC
nelifex

Thanks for taking the time to write this. That's all there was to it, no … Thanks for taking the time to write this. That's all there was to it, no code to identify the exact problem, just "class not registered" in a non-descript dialog box. The odd thing is that Chrome wouldn't open using the taskbar icon but would from it's location in Program Files. Other programs just wouldn't open at all. I think my Windows 8.1 update did a number on my registry as solutions to the fault usually requires deleting entries in RegEdit.Luckily I keep all my data backed up so last night I refreshed and reinstalled everything, updating Windows before any software went on. My only worry is that this problem didn't come up straight away - I installed 8.1 on Monday and problems showed on Friday...



The only reason I can think of that caused the issue to manifest itself several days later is that an installation had added an extension for Windows Explorer (perhaps codec packs that handles thumbnails within File Explorer). Windows 8.1 is very strict in registering COM objects and perhaps the installation failed to register properly which is congruent with being able to execute .exe files directly but not from the start menu (since the start menu usually refers to the application via links). Since the start menu refers to items via links, Windows Explorer has to look up via Explorer extensions how to access files with non EXE extensions. If one of the extensions is a COM object that failed to register properly, you will receive the "Class not registered" error.

Consequently, the issue is not Windows 8.1 itself, but rather how software installations register COM objects. I develop applications in Visual Studio and found that Windows 8.1 prevent me from registering my COM objects, because the problem is that Visual Studio runs under a user called "System" and Windows 8.1 only allows "Administrator" users to register. It's an annoying issue but also a very good security feature to prevent malware from registering their own malicious COM objects.
Original Poster
ElliottC

The only reason I can think of that caused the issue to manifest itself … The only reason I can think of that caused the issue to manifest itself several days later is that an installation had added an extension for Windows Explorer (perhaps codec packs that handles thumbnails within File Explorer). Windows 8.1 is very strict in registering COM objects and perhaps the installation failed to register properly which is congruent with being able to execute .exe files directly but not from the start menu (since the start menu usually refers to the application via links). Since the start menu refers to items via links, Windows Explorer has to look up via Explorer extensions how to access files with non EXE extensions. If one of the extensions is a COM object that failed to register properly, you will receive the "Class not registered" error.Consequently, the issue is not Windows 8.1 itself, but rather how software installations register COM objects. I develop applications in Visual Studio and found that Windows 8.1 prevent me from registering my COM objects, because the problem is that Visual Studio runs under a user called "System" and Windows 8.1 only allows "Administrator" users to register. It's an annoying issue but also a very good security feature to prevent malware from registering their own malicious COM objects.



Eloquently and thoughtfully put. Makes complete sense - this time around I refreshed to 8 then, besides an install of Chrome, updated through Windows Update and then, as soon as there were no more available, straight to 8.1.

If what you say is the case - which it certainly sounds to be although, if it makes any difference, the only account there has ever been on this PC has had Administrator privileges - then it's very bad from Microsoft. Having said that, Google hasn't blown up with this apparent issue so I'm probably in the minority
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