Solved Win 95: Windows protection error after setup

Microsoft Windows 95
May 7, 2011 at 12:08:39
Specs: Windows 95 & Windows 7, AMD Athlon II X2 250 3GHz / Host: 4 GB RAM, VM: 256MB RAM
I am trying to set up Windows 95 on a VM using Microsoft Virtual PC 2007 with a 8 GB VHD. Everything works fine until it finishes setup, but it when it tries to start Windows for the first time, it says, "While initializing device IOS: Windows protection error. You need to restart your computer."

I have tried booting up in safe mode and have formatted the VHD and reinstalled it several times, but I can't figure out why it won't work. It worked fine once before, but the hard drive it was on went bad, so I have to set it up again.

Thank you for any help/solutions.

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May 7, 2011 at 12:57:04
Just curious, is it Win95, Win95A, or Win95B/C you're trying to run? Sound's something like the old >350MHz AMD CPU error:

Just speculating here, but you may be able to change some of the settings in VPC2K7 to "allow" for a slower CPU speed (if that indeed is the problem). I've worked with VPC2K4, but not 2K7, so I don't for sure. You may also want to try a smaller VHD partition (2GB or less).

"Channeling the spirit of jboy..."

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May 8, 2011 at 11:47:57
If the above solutions don't work you can try bumping the VM down to between 128MB and 192MB; I routinely use 95 on my various systems with 64MB-128MB and don't know if it would even cache 256MB properly.

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May 9, 2011 at 22:27:38
✔ Best Answer
As stated above, you have encountered the well-documented >350MHz processor error with Windows 95. Another similar one exists at speeds >2.1GHz. Both issues can be fixed with updated system files from Microsoft patches.

I wrote a script to automate this and created bootable floppy/cd images to do so. See this thread at MSFN:

Also of note, one of the people who tested my patch was using Windows 95 in Virtual PC and had some input specific to that application. Begins at post # 44 on page 3.

Good luck!

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Related Solutions

May 30, 2011 at 07:56:44
Direct Download for AMDK6UPD.EXE:

Here's Microsoft's take:

Difficulties Using AMD K6-2 or Athlon Central Processing Unit

When you start your Windows 95-based or Windows 95 OEM Service Release- based computer that is using an AMD K6/2 (350MHz or faster), or an AMD Athlon (1.1GHz or faster), you may receive one of the following error messages:

* Device IOS failed to initialize. Windows Protection Error. You must reboot your computer.
* Windows Protection Error. You must reboot your computer.
* While initializing device IOS: Windows protection error.

NOTE: This problem is very intermittent on the K6/2 at 350 MHz, but occurs more often at higher speeds. This problem can also occur when you start your computer in Safe mode.

iMac G5 1.8GHz "Hero" PowerPC
2 x 1GB DDR PC3200 SDRAM
160GB WDC WD1600JD-40GBB2
Mac OS X Leopard Version 10.5.8

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June 5, 2011 at 13:46:59
Thank you very much. This solution worked perfectly.

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