Installing Windows 95B or 95C on Fast Systems
Last reviewed: March 2004
Errors installing, or first run of, Windows 95B or 95C on fast systems.
The following errors may occur when installing Microsoft Windows 95 (OSR1 or OSR2) on any computer with a AMD K6-2 (350MHz or faster), Intel Pentium III (1-GHz or faster) or a Intel Pentium 4 (any).
• 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.
Microsoft have supplied a patch that corrects this problem (Q192841). Microsoft says this patch applies to AMD K6-2 processors but it also applies to other chips such as the Intel Pentium III (1-GHz or faster) and all Pentium 4 processors.
Note: This fix applies only to Windows 95B & C (OEM 2.x)
Note: The fix does not correct the problem for the retail version of Windows 95.
Note: This does not apply to Win98, 98SE, or Me which come already fixed.
The patch does have an inbuilt uninstall feature.
[top of page]
The patch (amdk6upd.exe) fixes a software timing loop that is sensitive to processor frequency. It is not a processor error.
The error is a result of a divide exception in IOS.VXD, or a similar error within ESDI_506.PDR or SCSIPORT.PDR. Those files, and other associated files, must be updated.
The problem usually occurs during installation, or re-installation, of Windows 95.
[top of page]
THE PATCH: Windows 95 Update for Fast CPUs
Microsoft designed this update (Amdk6upd.exe) to be run from Explorer in Safe Mode. However some users can not get to Safe Mode after installing Win95B or C with a fast processor. Fortunately, a look at amdk6upd.exe using /? shows it can easily be extracted to a floppy.
Don't let the file name deceive you! It was named prematurely. It does work with other chips.
The Amdk6upd.exe patch installs/replaces 9 (or 8) files to your Windows 95B or C (details below).
One file, Ntkern.vxd, is replaced only if the version of Windows 95 is OSR2.1 or OSR2.5
This fix is only for Windows 95B & C (OEM SR versions 2, 2.1, and 2.5).
The fix does not correct the problem for the retail version of Windows 95, and does not apply to Win98, 98SE, or Me which come already fixed.
Caution: There's no guarantee that this fix will work for all users.
[top of page]
IDENTIFY your Windows Version
Use System Properties
If you can get to Safe Mode you can use System Properties.
Right-click on My Computer and select Properties.
Under the General tab, look at the System:
If you have a boot disk made by that Windows, you can boot with it and type VER at the DOS prompt.
An OEM SR2 system will show as 4.00.9500 B or 4.00.9500 C as the version. The number may vary slightly, but the letter will be a B or a C for the OSR2 version.