Why does System Protection (System Restore) show Max Usage at 100%?

Overview

The System Protection settings page may show Max Usage as 100% once NeuShield is installed.  However, this is misleading.  Even though it says 100% it won't actually use 100% of the disk space.  Windows has a task that will clean up the System Restore points to ensure that it is not taking too much disk space.

When NeuShield is installed it calls Microsoft APIs to enable System Protection and sets it to UNRESTRICTED.  The UNRESTRICTED option allows NeuShield to keep its snapshots as long as desired.  At this point the Windows GUI will say 100%, but Windows will still manage the size of it's own snapshots, which are temporary snapshots.  The NeuShield snapshots will be preserved until they are too old or no longer needed, at which point NeuShield will automatically delete them.

Permanent vs. Temporary Snapshots

All snapshots stored as part of Windows System Restore are stored as temporary snapshots.  Most 3rd party products also use temporary snapshots.  However, temporary snapshots are only stored for a short amount of time and then removed.  This means that the snapshots taken by the operating system will get removed regularly regardless of what the Max Usage is set to.

Because of this NeuShield uses permanent snapshots.  Permanent snapshots will remain until either Max Usage is reached or they are actively deleted.  Since NeuShield does not want outside entities to delete its snapshots it sets the Max Size to UNRESTRICTED to prevent them from getting aged out by the operating system.  In addition, NeuShield will block 3rd party products from deleting its snapshots.  This makes it so that only NeuShield can delete its own snapshots once they are too old or no longer needed.

More Changes Bigger Size

NeuShield will automatically remove older snapshots.  However, the amount of disk space used by System Protection may grow in size.  This is because the more changes that are made to the device the more space the snapshots will take.  These snapshots store the changes in real-time and will grow if the hard drive has had a large amount of changes to it in a short amount of time.  If this happens, there is nothing that needs to be done.  Over time these larger snapshots will be removed so that the disk space usage of System Protection will slowly return back to normal.  Typically it will take 1 to 2 weeks for the disk space to return back to normal after it has had a large amount of changes to it.

Restore Point Cleanup

NeuShield will delete its own permanent snapshots when they become too old or no longer needed.  The algorithm NeuShield uses for deleting its own snapshots is the following:

1. NeuShield keeps the most recent three snapshots regardless of how old they are.
2. NeuShield keeps the fourth snapshots that is at least 24 hours older to the third one.
3. NeuShield keeps the fifth snapshots that at least 48 hours older to the fourth one.
4. NeuShield keeps the sixth snapshots that at least 72 hours older to the fifth one.
5. NeuShield deletes all the rest that we don’t keep.

Manually Changing Max Usage

NeuShield stores data in the System Protection area for it's One-Click Restore feature and requires that there is enough space there.  If this is set too small the operating system may remove data that is needed by NeuShield.  Manually adjusting Max Usage could erroneously limit how much disk space NeuShield is allowed to use and cause some of its snapshots to get removed.  Also, changing this setting could cause Windows to use more disk space than it would in its default configuration.  This is why we recommend keeping this value set to the default, even though the GUI says 100%.

Resetting Max Usage To Default
If you have manually adjusted the Max Usage setting than it is recommend that you reset it back to it's default setting.  You can do this by doing the following:

1. Open up an administrator Command Prompt.
2. Run the following command:
   1. vssadmin resize ShadowStorage /For=C: /On=C: /MaxSize=UNBOUNDED

View All Snapshots

If you want to see all the snapshots on your computer that are using up disk space you can run the following command to see them:

1. Open up an administrator Command Prompt.
2. Run the following command:
   1. vssadmin list shadows