How to Backup the Windows Registry


In simple terms the Windows Registry can be thought of as a file containing an extended inventory of all your PCs hardware and software.

When Windows starts up it consults the Registry in order to know how to relate to your specific hardware and software.

It's a file that's essential to Windows. If it gets corrupted Windows won't be able to function properly.

And it does get corrupted; rather too often actually. That's why it's good practice to have a backup copy.

Easy, you say, I'll just copy the file to another location.

In Windows 95, 98 you can do just this. The Registry consists of two files system.dat and user.dat located in the Windows folder and you can simply copy these to another folder to create your registry backup. ME adds a third file, classes.dat, but it too can be simply copied.

This simple approach won't work with Windows NT and later versions as the Registry files are locked by the system and can't be easily copied.

Windows addresses this by providing automatic backup of the Registry as part of the automatic System Restore feature. This feature is enabled by default when Windows is installed.

If you have left the System Restore feature enabled on your PC then your Registry is automatically being backed up. If it gets corrupted Windows will automatically try to recover it from previous restore points.

However, many users, me included, turn the System Restore feature off as it is a notorious disk space hog. Once turned off, your Registry is no longer being backed up.

Thankfully, there are a number of utilities that will back up your Registry. One of the best is also free. It called ERUNT.

ERUNT (Emergency Recovery Utility for NT) will backup the Registry for all Windows systems from NT onwards. It also allows you to recover from backup either through a special recovery program or through the Windows Recovery Console.

And it's fast, very fast.

With ERUNT it's also possible to set up automatic Registry backups using the Windows Scheduler.

As a bonus, ERUNT includes another utility NTREGOPT that allows you to defragment your Registry. To be frank, I've never myself seen any performance improvement from registry defragging but then again it does no harm either.

ERUNT is easy to use but it's not intended for raw beginners. Raw beginners will most likely have System Restore enabled anyway so they won't need to back up their Registry.

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by SA Jack on 31. May 2013 - 13:50  (108181)

In reference to johnvk's comments last month regarding's Registry Backup. I've been using it for about 6-months. With very few exceptions, the backup works perfectly. The rare problems have to do with Volume Shadow Copy not working correctly. When that happens, I do get a backup of my account, however, other user accounts are excluded. I've seen one consistent possible problem that I've reported to Shane sometime back and that has to do with Windows Reliability Monitor showing an application error that the program "stopped working". This occurs every day, even though the registry backup and log files are fine. As yet the problem has not been addressed. Check to see if this is a problem on your system as well. I'm running Windows 8 Pro x64. -SA Jack

by johnvk on 16. April 2013 - 3:51  (107126)

ERUNT vs Registry Backup?

ERUNT sounds great because it backups up the actual FILES rather than the "contents" and so if your system doesnt boot (and thus many other backup/restore methods are unavailable) you can use the venerable COPY dos command to restore. Or ERUNT.exe can do it for you.

But (who's "Windows Repair (All In One)" is recommended on this site and i've used it twice with splended success) also has a Registry Backup.

It talks about 2 possible problems with ERUNT

1. not backing up other users, just the current one.
2. perhaps invalidating other programs' handles (presumably to the registry)

Quoting that page:

A lot of registry backup programs use the RegSaveKey API, such as ERUNT. When using the API you can only backup loaded registry files. [Only the current user's registry NTUSER.DAT file is loaded, and so only it is backed up.] - Registry Backup uses the volume shadow copy service instead. This allows perfect backups of the registry files and all profiles on the system.


Quote From Microsoft:
"Applications that back up or restore system state including system files and registry hives should use the Volume Shadow Copy Service instead of the registry functions."

"Using RegSaveKey together with RegRestoreKey to copy subtrees in the registry is not recommended. This method does not trigger notifications and can invalidate handles used by other applications."

By using the Volume Shadow Copy instead of the RegSaveKey API this registry backup program is safer to use.

End quote.

Have people used Registry Backup and found it reliable, as they have ERUNT? Is it really safer than ERUNT, as its author claims? I'm not sure i *want* to trigger those notifications when i'm backing up the registry. That's nobody's business, right? But what about that "invalidate handles used by other applications"? I can see that might be a problem when *restoring* using RegRestoreKey--maybe that doesnt trigger the handle. But on save? Who needs to see that? Or is Micro$oft just trying to make sure *their* digital eyes see everything. So i would like opinions on this.

And the backing up of other users is valid, ERUNT even says so.; What do people think of that?

(Also there is a comment on this page that appears to be spam with pseudo-legitimate text (probably to avoid auto-spam-detection): "Anonymous on 18. March 2009 - 0:12 (18073)")

by MidnightCowboy on 16. April 2013 - 5:17  (107127)

Beware of the scam "free scan for hidden Windows errors" link at the top of the page containing their registry backup which points to a site with a deserved poor WOT (Web Of Trust) rating. Ethically compliant sites should not carry this rogue garbage just to make money. MC - Site Manager.

by vasa1 on 31. August 2010 - 6:57  (57025)

I've never thought about using ERUNT because I've been using the Eusing Registry Cleaner (also recommended by Gizmo) for years and it creates a "backup" as a single .reg file.

My system is Win XP SP3. Yesterday, for the first time ever, I looked at the size of this backup. It was ~69 MB. Is that okay, considering that I run the cleaner after uninstalling software? (Admission: I don't know anything about this registry business but if it can be beneficial, I don't mind learning!)

by majoMo on 31. August 2010 - 12:10  (57038)

@ vasa1,
- I use also Eusing. However to do a "Full Registry Backup" it is not suitable with it. Why?
1. It is in AINSI or Unicode format (.reg format); not in binary format. This is crucial (the Registry storage is done in binary format).
2. All versions of RegEdit contain serious bugs which cause you to loose registry data of certain kinds. Furthermore, registration files do not store any class information, security descriptors and make no distinction between volatile and non-volatile keys.
3. The best way is to use ERUNT; if you have a problem (e.g. a corrupted Registry) by any reason, or you want to restore the entire Registry - the way is ERUNT. If your PC doesn't boot and you have a boot disc like BartPE, you can restore all registry easily, clicking in 'ERDNT.EXE' that is usually in "C:\WINDOWS\ERDNT" (pls see also post #52462 by LRC1962, e.g).

«Is that okay, considering that I run the cleaner after uninstalling software?»

Yes is Ok. All the Registry is there (but not in binary format, that is better to backup; it's a .reg file). Eusing after cleaning the registry does a backup file for removed files also, that is good if some annoyances the user see in their OS after the cleaning process).

by vasa1 on 31. August 2010 - 12:14  (57039)

Thanks, mojoMo! It looks like the safe thing to do is to have ERUNT and to backup the registry as a safety precaution.

by majoMo on 31. August 2010 - 12:36  (57042)

You are welcomed, vasa1.

by Charly (not verified) on 25. August 2010 - 19:10  (56711)

I have Paragon backup and recovery installed. Would ERUNT &/or NTREGOPT supply additional services for me or would it/they just be redundant? Any info appreciated. Thanks

by Chris Kavanagh (not verified) on 18. August 2011 - 17:17  (77907)

I just used ntregopt for the 1st time, & WOA NELLY, I cannot believe it. My PC is running like brand new. I happened to glance at my swap usage, & it's gone down from 40%-45% down to the mid 30%. I don't know why this happened, but it did. My PC had been running terribly slow, especially w/Firefox.I knew I needed more memory (only have 756mb's) & still do because the memory usage is in the 80% up to the high 90's% most of the time. But, because the swap usage has gone down so much,it's not being slowed down. So, YES, I think you can get some advantages out of Erunt & Ntregopt.

by kendall.a on 25. August 2010 - 21:05  (56716)

These are 2 very different types of programs with 2 very different purposes. ERUNT only backs up your registry. It does a great job. It is very useful for restoring your registry if it gets corrupted. In a lot of ways, it is much like System Restore; only a little better in my opinion.

Paragon Backup & Recovery is probably a file/document program and might even be an imaging program. It backs up files/documents. It might even create an image of your system, which you can use to bring your system back exactly to the way it was when you made the image.

If you are only making backups of your files/documents, then I think ERUNT could be useful. However, if you are making image backups, then I see little need for ERUNT.

by Charly (not verified) on 3. September 2010 - 21:06  (57226)

Sorry Kendal, I just got this reply. thanks for the info. If I read U correctly. them my Paragon program. which can do Backup and Imaging has it covered, and ERUNT would be redundant for me. I also have REVO Uninstaller Pro as well, and it does a systems backup whenever I install or uninstall something using it's program.

by John cook (not verified) on 8. November 2012 - 18:38  (102043)

I realize this comment is late, however it may help others.

First, please realize that ERUNT backs up the registry differently than other reg applications. Where most registry apps only back up a few of the hive files, ERUNT backs them all up, thus preventing almost all reg related catastrophes.

Secondly, ERUNT, as a command line utility can be utilized in numerous ways. It can be setup to capture the current registry at boot, at a particular time using Windows schedule, on command, and to run before any setup.exe command. I have all four and I have limited ERUNT to saving a week's worth before it begins to overwrite previous saves. I have the file name constructed to allow me recognition of each type of save. In this method, I am so well covered that I have not lost a thing in over seven years and my system is as fast as it began long ago. Also, I do not use the silly Windows restore app, and have removed it completely. All of my operating systems have, over time, become tiny and fast. 7 is really trick to get into a tiny configuration, but it screams when you get it right. No, I am not interested in writing out my methods, please do not ask. It is an extensive process and I am in my seventies now and too tired to get into it. You young kids can figure it out if I can.

I also run highly modified Windows XP SP3, 7, and Linux OS's in a triple booter. The Windows systems are setup on eight different partitions with XP and 7 sharing program files and the swapfile. I also placed Program files and Documents and settings on separate partitions with the Windows kernel only on Drives D: and E: In that manner, Windows has remained stable and fast. This is not a beginners method, and it is a bit tricky and techy, but anyone who wishes to study should be able to create it.

So, be aware, regardless of the alternative registry back up you use, it is not equal to or better than ERUNT. Using it and the OS setups like I have mentioned above Windows has become a viable system--finally!

by LRC1962 on 19. June 2010 - 14:26  (52462)

Erunt - don't leave home without it. Got home last night and found a missing or corrupt ~/system file message on a black screen. That means the reg files. Took a lot of searching and fussing to get me into safe mode (only time this has happened to me. Went to my Erunt saved files ran the restore program and was back in business 5 minutes later. Beats to pieces the procedure you would have to go through in the same circumstance using System Restore and from what I have read it is not always reliable.

by Anonymous on 18. June 2010 - 15:12  (52404)

I've been using ERUNT, including NTREGOPT, for a long time now on both XP Home SP3 and Vista HP SP1, however, I cannot get the AUTOBACK automatic backup feature to work on Windows 7 Starter. I have run the two programs successfully and reinstalled, and also tried to make a shortcut to it myself, but no go: when I reboot my Windows 7, it tells me AUTOBACK is a command line utility, does not run it, and when I look the shortcut is gone from Startup. Any advice?

by kendall.a on 18. June 2010 - 22:45  (52435)

Please see this link for a discussion about Erunt and Windows 7. It might be your answer:

by Anonymous on 18. June 2010 - 15:15  (52406)

I should add that Windows 7 UAC is off. In addition, while AUTOBACK works on Vista, UAC stops it and you must click the system tray icon for blocked startup programs to tell the computer to let it run; the use of Norton UAC was of no help in this.

by Anonymous on 26. February 2010 - 23:37  (44582)

Does anyone know if you should use NTRegOpt or PageDefrag first (assuming you wanted to use both)?

by Anonymous on 15. January 2010 - 17:53  (41134)

While deragmenting the registry will not normally bring you any perceptible performance increase. it does have one certain advantage, and that is it reduces registry size, which makes it quicker to back up.

In my opinion this is also the only advantage of a "cleaner" for the registry.

NOTE: NTREGOPT does not "clean" or alter the registry, it merely optimises it to remove free spaces and thus reduce the size.

To quote the developer;

The program works by recreating each registry hive "from scratch", thus removing any slack space that may be left from previously modified or deleted keys.

Note that the program does NOT change the contents of the registry in any way, nor does it physically defrag the registry files on the drive (as the PageDefrag program from SysInternals does). The optimization done by NTREGOPT is simply compacting the registry hives to the minimum size possible.

by Anonymous on 17. April 2009 - 10:36  (20023)

i have been using this for maybe a month now, i find it very simple to understand and easy to use,

by Anonymous on 18. March 2009 - 5:12  (18073)

Thanks, I thought undoubted would betoken alright now the download domicile says veritable is Vista compatible.

by Anonymous on 5. August 2008 - 9:49  (5588)

Ntregopt is still one of the best defrag and compact registry utilities, it does the job in a single pass and it's compatible with NT/2000/2003/XP/Vista. I tested it against Registry Mechanic v8 and Auslogics Registry Defrag scoring 99,7%-100% against both, and performed better than Winaso and Resplendence Registrar built in defraggers. Other popular registry defraggers include Quicksys, Page Defrag and Free Registry Defrag, but I did not test them.

by Anonymous on 19. July 2008 - 17:29  (4527)

NTREGOPT says "This program optimize the registry files of your Windows NT/2000/XP system."

Does this mean it is unsafe for Vista?

by Anonymous on 19. July 2008 - 18:08  (4529)

I'm using it for the past 8 months without a single problem. 2 of my favorite apps.

by Anonymous on 4. September 2008 - 13:08  (7341)

I have absolutely no problems using NTREGOPT in Vista. You should run it elevated though, or run using Scheduler:

by Anonymous on 19. July 2008 - 18:36  (4530)

Thanks, I thought it would be alright since the download site says it is Vista compatible.

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