Some Windows 10 users with May 2019 update are seeing a new partition called PortableBaseLayer. If this is your first time, you might wonder what in the world is the PortableBaseLayer partition.

What is PortableBaseLayer Partition?

Before you ask me, no, PortableBaseLayer is not a virus, malware, or rouge partition.

PortableBaseLayer is a system partition created for Windows Sandbox.

When you enable the Windows Sandbox, the operating system will automatically create the PortableBaseLayer partition and places all the important files that are necessary to run the sandbox.

Depending on your usage, the partition size will be anywhere from 1GB to 10GB. Sometimes, it might even exceed that range too.

In case you don’t know, Windows Sandbox is what it sounds like. It is a built-in sandbox that lets you test programs and settings without affecting the host operating system. Compared to traditional solutions like VMware and VirtualBox, Windows Sandbox is lightweight, fast, and easy to use.