Steps to reproduce:

1) Open Unity and click on 'New' to create a new project
2) In the 'Project name' field, write down " Test, " (make sure comma symbol is included in the name)
3) Hit 'Create Project' button
Editor will crash or throw an error:
Failed to resolve packages:Manifest

Expected result: Project should be created and opened without any problem
Actual result: Editor crash/error while initializing created project

Reproduced with:
2017.2.0b6, 2017.2.0f3, 2017.3.0b3

Not reproduced with:
2017.2.0b5

Regression since:
2017.2.0b6

Tested using windows 10 machine
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Fixed in: 2018.1.0a4