On a legacy Windows or MS-DOS computer, if you encounter IOS (“input/output system”) errors, follow these troubleshooting steps.

Bad file or statement in the config.sys or autoexec.bat

The following steps should resolve the error “While initializing device IOS: Error: An I/O subsystem driver failed to load” at boot.

Temporarily rename your autoexec.bat and config.sys by following these steps:

  • Boot the computer to MS-DOS.
  • Once at the DOS prompt, type:

C: cd\ ren autoexec.bat autoexec.ch ren config.sys config.ch

  • Once the above steps are completed, reboot the computer.

  • How to restart Microsoft Windows.

  • See our autoexec.bat and config.sys guide for additional help with these files.

Issue with smartdrv.exe or rmm.pdr

The following steps can resolve any of the following errors:

  • Windows protection error.
  • IOS error.
  • While initializing device IOS: Windows protection error. You must restart your computer.
  • While initializing IOS: Windows protection error. You need to restart your computer.
  • Windows initializing device IOS: Windows protection error. IOS failed to initialize, please restart.
  • Windows initializing device IOS: Windows protection error. You need to restart your computer" in Windows 95.

Temporarily rename the smartdrv.exe and the rmm.pdr by following the following steps.

  • Boot the computer to an MS-DOS prompt.

  • How to get to an MS-DOS prompt or Windows command line.

  • Once at the DOS prompt, type:

C: cd\windows ren smartdrv.exe smartdrv.ch

  • Once smartdrv.exe is temporarily renamed, reboot the computer to determine if the issue is still present.

If the issue persists, rename the rmm.pdr by following the following steps.

  • Boot the computer to an MS-DOS prompt.
  • Once at the DOS prompt, type:

C: cd\windows\system\iosubsys attrib rmm.pdr -r -s -h ren rmm.pdr rmm.ch

  • Once rmm.pdr is temporarily renamed, reboot the computer to determine if the issue is still present.

Issue with Windows 95 and AMD K6/2 (350 MHz or faster), or an Athlon (1.1 GHz or faster)

The following steps and information should help resolve “Device IOS failed to initialize. Windows Protection Error. You must reboot your computer.”

This issue is attributed to a divide exception in Ios.vxd. It’s a limitation of the software, and is not indicative of a problem with the processor itself, which is functioning properly. This issue is resolved in Windows 98 and all later releases of the Microsoft operating systems.

Other Windows corruption

If, after following the above recommendations you cannot resolve the issue, it’s likely your Windows installation is corrupted. In this case, we strongly recommended you format and reinstall Windows.

  • How to erase my hard drive and start over?
  • Computer operating system help and support.