0x81000037, 0x80070001 & 0x80070003 are errors caused by Windows encountering a “reparse point” inside a folder which you're trying to back-up.
Microsoft mentions that “reparse points” are the Windows equivalent to symbolic links in Linux. They allow you to “link” a folder to a different location on your hard drive, without having to move the folder.
The reason the error shows is because when Windows attempts to “backup” the folder in question, it cannot find the file that's linked inside it. This makes Windows think that the file doesn't exist, is inaccessible, or corrupted.
The errors will generally appear with these messages:
0x81000037: Windows Backup failed while trying to read from the shadow copy on one of the volumes being backed up
0x80070001: (Invalid Function)
To fix them, you have to remove any reparse points inside the folders you're trying to back-up.
The main cause of the problem is that Windows does not recognize the location of a file.
The error may appear when using Windows Update, scheduling a Restore Point or generally show when you are using your system.
To fully understand the problem, you have to appreciate that whenever you use a personal computer, all it's doing is processing billions of lines of code – much of which are stored in “files” on your persistent storage device (either Hard Drive or SSD).
In most OS systems, you can actually allow applications to load particular files by way of “linking” them to other hard drive locations.
For example, you may have a saved game file in your “Saved Games” folder – which you will be able to include in your actual game folder by way of a “symbolic link”.
The SymLink functionality is native to Linux, and Mac uses it too. Windows being Windows, it doesn't use “symbolic links” – but “reparse points”. The functionality is the same in both cases.
The errors you're experiencing are caused by your system being unable to load particular files – due to its lack of physical presence on the drive. To fix it, you need to fix the underlying bugs causing the error to show.
The way to fix the problem is to ensure that you're able to clean up any of the folders that may be causing issues with “reparse points”.
Microsoft gives 3 ways to resolve the problem:
- Reparse point directs to a volume that uses FAT as the file system
- Reparse point is a “mounted volume” that contains compressed files (EG zip files etc)
- Reparse point directs to the “root” of another volume
To resolve, you should follow the steps outlined below:
1. Remove Any “Mounted Volumes” / “Reparse Points”
The first step is to ensure that you don't have any “mounted volumes” or “reparse points” on your system.
This might sound complicated, but is actually relatively simple:
- On your keyboard, press “Windows” + “R” keys
- This will bring up the “Run” dialogue – into it type “cmd” and press “Enter”
- From the cmd prompt that appears, type “DIR /AL /S” and press “Enter”
- This should show a list of the directories classed as “Reparse Points”
- From the list, take the ones you feel are corrupting the backup, browse to them in “File Explorer”
- When you identify the folder, right-click the volume and check if it says “Mounted Volume”
- If it is, delete it by holding SHIFT and pressing DELETE
- Once this has completed, restart your computer
After the restart, you should be able to test out what you were attempting to do before.
If the error disappears, it means that the problem has been resolved; if not, you'll need to move onto the next steps.
2. Ensure Permissions
Next, the other problem you may have lies in the permissions of the system.Permissions are used in computing to determine which users can – and cannot – manage various resources within the system, and is typically based around “user roles” (admin etc).
To ensure that the errors are not replicated, you may be experiencing issues with regard to the way in which your user account is able to access particular files / settings.
To fix this, you need to be able to correct any permissions issues your system may have:
- Go to the folder(s) you're trying to backup / restore
- Right-click on the folder and select “Properties”
- From the “properties” dialogue, select “Security”
- In here, press “Edit”
- From the window that appears, type “Everyone” in the box and click “Check Names”
- If the “Everyone” text becomes underlined, click “OK”
- With “Everyone” selected, click “Allow” for “Full Control” in the bottom panel
- Click “OK”
- Try backup / restore again
If this doesn't work, make sure you repeat the process for any other folder you're trying to backup. Whilst it should not be an issue for most users, it will likely cause problems *if* your system has a lot of use (permissions not working etc). Further issues will likely be caused by some sort of “block” on the folders, either from antivirus or perhaps a virus infection on the system.
3. Clean Out Viruses / Malware
Next, your computer *may* have issues with virus / malware infections.
Whilst this may not seem like a cause of a file-system error, the problem lies in the way that many newer viruses end up targeting underlying files / folders, in order to block user access OR ensure that the infection has the ability to perform its nefarious work.
The point is that if you're still experiencing the errors, it may be caused by a virus infection temporarily overwriting certain files/folders on your hard drive.
To fix this, you need to ensure you have adequate virus / malware protection:
- Download MalwareBytes (free)
- Save and install it onto your PC
- Open the zip file and then run the software inside
- When the software runs, set it to perform a full scan
- After the scan completes, restart your system
Unlike viruses, “malware” (malicious software) often disguises itself as legitimate software applications, only causing problems *after* they gain access to your PC.
MalwareBytes is the only tool entirely dedicated to removing malicious infections from Windows systems. If after performing the steps above, and cleaning out any potential malware threats, you find Windows still unable to perform a backup, you'll be best seeking the opinion of someone with more specific knowledge of your system. You may also want to disable any antivirus applications you have running as these could conflict with (block) the backup process.
4. Run “Troubleshooter” Tools
If you're still experiencing the error, you should run one of the “troubleshooters” inside Windows 10.
The troubleshooter systems inside W10 actually relatively effective, and work as follows:
- Click on the “Start” button (bottom left taskbar)
- Select the “cog” / “Settings” icon from the left “charms” menu (just above the power button)
- When the “Settings” screen loads, click on “Update & Security”
- From the left menu, select “Troubleshoot”
- From the list that appears, you should first click on “Windows Update” and then any other which pertains to what you're trying to do
- A small applet will load up – let it run and then just let it clean out any of the issues it finds
- Once complete, restart your PC
This will generally resolve any of the core issues that Windows 10 has preventing the likes of Windows Update working. It's not guaranteed to work, but it works for many common errors that inhibit the core functionality of W10.
5. Run SFC/DISM
Finally, if you don't have any success with the above, running the SFC (System Files Checker) & DISM (Deployment Image Servicing and Management) tools are a great way to ensure the core Windows system is running as effectively as possible.
To do this, you need to follow the steps outlined here:
- Press “Windows” + “S” keys on your keyboard
- Type “CMD” into the search box
- From the list that appears, right-click on the top listing and select “Run as Administrator”
- When the CMD window loads, type “SFC /scannow” and press “Enter”
- After this completes, type “DISM /Online /Cleanup-Image /RestoreHealth” and press “Enter”
- Once this completes, restart your system
If the errors persist beyond these steps, it suggests a more specific issue with your particular system – which an Internet article will not be able to resolve on its own.
Further steps to resolve the error would need to involve someone who has specific access to your specific Windows system. To do this, there are a number of services online which can help – including the likes of SuperUser and Microsoft Answers. If you need more specific support, you may wish to contact a dedicated technician, although that will involve paying someone.