Reproduction steps:
1. Open Unity editor
2. Select New+
3. Insert invalid location, e.g. Y:\
4. Select "Create project"

Expected result: "cannot create a project at Y:\" error is shown with some details about the reported Windows file system error.
Actual result: "Failed to load window layout" error is displayed (see attached screenshot)

Reproducible with: 5.6.5p1, 2017.1.3f1, 2017.3.0p3, 2018.1.0a2
Not reproducible with: 2017.2.1p2, 2018.1.0a3, 2018.1.0b1, 2018.1.0b4

Notes:
- in Unity editor version 2017.2.1p2 editor crashed and windows message "Unity editor has stopped working" is shown
- in Unity editor versions 2018.1.0a3-b4 no error message is shown, but the editor process can be observed as active in the Task Manager