In Windows 10 Build 1903, Microsoft has enabled the "Launch folder windows in a separate process" option by default. This causes each folder you open in File Explorer to use its own process, and if one hangs, it does not affect the rest of the open folders or the desktop.
Previously when an open folder stopped responding in Windows and you closed it, it would cause the entire desktop to restart. This would cause all of your taskbar items to be shuffled and your open explorer folders to close.
With the
Folder Options ->
Launch folder windows in a separate process option enabled this behavior changes. As each open folder runs in its own process, if one folder stops responding and you close it, it will only affect that one folder and nothing else in Windows is affected.
Previously this option was not enabled by default, but with the upcoming release of the April 2019 Update, aka build 1903, Microsoft has enabled this option by default.
When enabled, you will continue to see a Windows Explorer process in the Apps section of the Task Manager with all of your open folder windows displayed underneath it as shown below.
The difference now is that if you select the main Windows Explorer (5) task as shown above, and click Restart, Windows will just close all the open File Explorer windows and not restart the Windows Desktop. Previously, it would also close the Windows Explorer processes associated with the desktop and thus the desktop would be restarted.
It is not known why this setting was not previously enabled by default, other than that it may cause an increase in memory and CPU utilization due to the use of additional processes. With the greater system requirements of PCs running Windows 10, Microsoft may have decided that computers are powerful enough to not feel the effects of the additional processes.
source
