How to restore the Path environment variable I deleted?

I lost my PATH with a program install earlier today, but with all the existing programs already running, it was easy to get it back. If you have a command window open, run:

echo %PATH%

If you don't, you can look at the environment variables of currently-running programs with Process Explorer (procexp).

I followed the advice in the answer to a related question here and recovered my previous path setting as of this morning using regedit. Expanding a bit on that answer, here's how I did it. (Read the linked answer to get the full instructions, I don't provide all the details here.)

I selected my earliest backup from today (11:43 AM timestamp in 'Today' section)

and examined the earliest ControlSet within the HKEY_LOCAL_MACHINE/System node of that copy of the registry file, ControlSet002:

and copied out the previous value of my path variable from the key Control\Session Manager\Environment\Path within that level.

Your mileage may vary, as I don't know exactly what triggers the backup of the registry.

• From the start menu, open Run (or press ⊞ Win+R).
• Type regedit
  • Find HKEY_LOCAL_MACHINE folder
  • Go to the SYSTEM folder
  • Go to the ControlSet002 folder
  • Go to Control folder
  • Go to Session Manager
  • Go to Environment folder
  • Then, inside Environment folder, double click Path

The previous Path should be there.

You could do a system restore.

To restore your PC using System Restore

Swipe in from the right edge of the screen, and then tap Search. (If you're using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then click Search.) Enter Recovery in the search box, tap or click Settings, and then tap or click Recovery.

Tap or click Open System Restore, and follow the prompts.

"Restoring" from a default set is another option, with the risk of some installed apps complaining until fixed.
Background: Happened when launching WLM after a reboot. The only thread with information regarding the missing WLDcore.dll suggested a missing PATH environment variable.
Before the said reboot, there was an admin PS console open in the attempt to make Curl accept commands. Must have knocked out the PATH variable with it somehow.

Fortunately, and unfortunately, Brink's default PATH values were copied to System Properties\Environment Variables before accessing the values from ControlSet001 (no ControlSet002 here) referred to in other answers in this thread. So the only option to recover the original values was with the system restore also mentioned in this thread. A good thing is the apps that use PATH on this machine document their requirements of it, so easy to repair.

For those who experienced similar, here's Brink's Windows 10 values:

%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Windows Live\Shared

And his bare minimum for previous OSes:

%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\