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Backing Up the Registry

by Don Penlington

Backing up the Registry

Don Penlington

You should regularly make a backup of all your registry files. This is particularly important on a new computer, or immediately following a Windows reinstall. You will then have a nice uncluttered registry to return to at any time in the future. Your registry will inevitably become so cluttered in time that performance will slow down or become erratic. Your only other remedy then may be to reinstall Windows, which sometimes isn't very successful if done "over the top".

You will find the backup program ERU on the Windows 95 Disk under Other/Misc. Transfer it onto your hard drive. If you just want to backup User.dat and System.dat (the two most important registry files) you can simply run Regedit and "export" the whole registry manually by clicking the "export" option. It will appear as a .reg file and will be restored automatically when you double-click it.

It's a good idea to do this before installing any major piece of software, in case you need to restore your old registry if the new software turns out to be a disaster. ERU will not only copy these registry files, but several other important system files as well, so is more thorough than a Regedit export. Don't wait till your computer starts to go wrong---by then it's too late to start thinking about making a backup. It is not sufficient to rely on the automatic emergency backups User.dao and System.dao.

Windows 98 makes emergency registry backups each time it reboots---make sure you keep a permanent early copy either on floppy or on your hard drive, then retain another current copy each month or two.

Instructions for Emergency Recovery Utility (ERU)


First make a master backup on floppy for emergency use. To do this

  • Open ERU.exe
  • Insert Floppy
  • Select A Drive (if that is your floppy drive)
  • Click next and follow directions.
  • Backup all files shown. Should take less than a minute.*

You'll probably never need to use this disk but might help if ever you inadvertently lose your other backup files.

Then do a backup of the same files to your Hard-drive. This is what you will normally use whenever you want to restore your Registry. To do this:

  • Open ERU.exe
  • Select "Other" (drive)
  • Type in the path and a name for your backup**
  • Backup all files shown


*If your User.dat or System.dat files are too bloated to fit on 1 floppy, you may have to back up one or both of these separately. Use "Custom" and deselect whichever one won't fit.

**I suggest "C:\erdaug"---i.e. your root (main hard drive) directory, (usually C ) then erd followed by the month. I have at present 3 backup files available---erdaug for the latest one, erdjun for one I did in June when the machine was running nicely, and erd may for a bare-bones one I did in May after a Windows install. Keep the filename to 6 letters.


For routine replacement of Registry after crash or if things start going a bit funny or slow or if you feel the system is getting a bit "heavy" and sluggish:

  • Open in Dos at Command prompt only.
  • Type cd erdaug (or whatever the filename is--don't forget the space)
  • Press Enter
  • Type erd.exe [press enter]

A window should come up with several choices. Use arrows to select "Start recovery". Press Enter.

Recovery should take just a few seconds. It is replacing all your Registry files. Press Enter again.

You will then return to the dos line "C:\erdaug" Type "win" and press Enter to return to Windows.

That's all, folks!

Don Penlington


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