Download migrated config from Migration tool not working

Question

Frustratingly I have got the VM setup, loaded an SG backup, completed the migration, edited in Preview... all working great... but when i come to try and download the resulting file backup for XG it just goes to blank web page. 
 URL is like: 10.10.72.44/.../Controller 
 Tried Firefox and Chrome, no joy. 
 Anyone got a suggestion for what's wrong?

LuCar Toni · Accepted Answer

Did you use a "Space" ( ) in the name of the migration? 
 This can lead to such issues.

aapercy · Answer

That was it - space in migration project name. 
 Unfortunately not possible to edit that, so started a new project with same backup and migrated backup downloads just fine. 
 
 Thanks!