# " RPC-SERVER IS UNAVAILABLE " Robotstudio Error message.

**URL:** <https://tech-community.robotics.abb.com/t/rpc-server-is-unavailable-robotstudio-error-message/12070>\
**Category:** RobotStudio\
**Tags:** fatal-error-robotstudio, error, robotstudio\
**Created:** [November 3, 2025, 1:38pm UTC](https://tech-community.robotics.abb.com/t/rpc-server-is-unavailable-robotstudio-error-message/12070 "2025-11-03T13:38:11Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![bran21](https://avatars.discourse-cdn.com/v4/letter/b/7ab992/32.png) [@bran21](https://tech-community.robotics.abb.com/u/bran21)\
**Post date:** [November 3, 2025, 1:38pm UTC](https://tech-community.robotics.abb.com/t/rpc-server-is-unavailable-robotstudio-error-message/12070/1 "2025-11-03T13:38:11Z")

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Hello, I keep trying to open a robotstudio project and my virtual controllers won’t ever start and stay in the ‘stopped’ state as well as get these error messages below:

1. ‘The RPC is unavailable’.
2. ‘RObAPI exception’.
3. ‘There was a problem starting your virtual controller’.

Any insight on how to resolve this? I have restarted my computer and everything. Any help is greatly appreciated!

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<div class="post-metadata">

**Author:** ![bran21](https://avatars.discourse-cdn.com/v4/letter/b/7ab992/32.png) [@bran21](https://tech-community.robotics.abb.com/u/bran21)\
**Post date:** [November 3, 2025, 2:23pm UTC](https://tech-community.robotics.abb.com/t/rpc-server-is-unavailable-robotstudio-error-message/12070/2 "2025-11-03T14:23:36Z")

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update: It is now working, but this happens every so often… I have to open and close the project until I get the message ’  
Robotstudio has detected one or more virtual controllers running, do you want to terminate the virtual controllers?’ and I click ‘yes’

That is the only fix to this solution I’ve found, but not sure what causes it.

I don’t have any other applications opened etc, this computer is detected to RS only, so I’m wondering what is causing this error.