# RobotStudio 2020.4 not working

**URL:** <https://tech-community.robotics.abb.com/t/robotstudio-2020-4-not-working/9963>\
**Category:** RobotStudio\
**Created:** [January 30, 2021, 8:33pm UTC](https://tech-community.robotics.abb.com/t/robotstudio-2020-4-not-working/9963 "2021-01-30T20:33:21Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![cpvicent](https://avatars.discourse-cdn.com/v4/letter/c/dc4da7/32.png) [@cpvicent](https://tech-community.robotics.abb.com/u/cpvicent)\
**Post date:** [January 30, 2021, 8:33pm UTC](https://tech-community.robotics.abb.com/t/robotstudio-2020-4-not-working/9963/1 "2021-01-30T20:33:21Z")

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Just updated to RS2020.4.  
Now when I open an existing station the program goes into an endless loop of building collision sets even though there are no collision sets active!  
Then it takes forever to start the robot VC.  
I previously had RS2020.3 and it was working flawless.  
I there a fix for this?  
How can I revert back to 2020.3?

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**Author:** ![mritter](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@mritter](https://tech-community.robotics.abb.com/u/mritter)\
**Post date:** [February 23, 2021, 10:06pm UTC](https://tech-community.robotics.abb.com/t/robotstudio-2020-4-not-working/9963/2 "2021-02-23T22:06:22Z")

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[https://robotstudiocdn.azureedge.net/install/RobotStudio.2020.3.zip](https://robotstudiocdn.azureedge.net/install/RobotStudio.2020.3.zip)

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**Author:** ![Maxim](https://dub1.discourse-cdn.com/flex005/user_avatar/tech-community.robotics.abb.com/maxim/32/4429_2.png) [@Maxim](https://tech-community.robotics.abb.com/u/Maxim)\
**Post date:** [February 24, 2021, 6:17am UTC](https://tech-community.robotics.abb.com/t/robotstudio-2020-4-not-working/9963/3 "2021-02-24T06:17:22Z")

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Never heard of this issue before.

Did you manage to get it resolved?