# What Is the Cause of the Failure to Install a Guest OS Driver on a Windows ECS?

Possible causes:

- Your image file was exported from a VMware VM, and VMware Tools was not uninstalled or not completely uninstalled.

- You have downloaded the Guest OS driver of an incorrect version for your Windows ECS.
- The disk space available for installing the Guest OS driver is insufficient. Ensure that the disk where the Guest OS driver is installed has at least 300 MB space available.

Parent topic: Image Optimization