# RS 2019.5 issues

**URL:** <https://tech-community.robotics.abb.com/t/rs-2019-5-issues/9255>\
**Category:** UpFeed\
**Created:** [January 3, 2020, 7:13am UTC](https://tech-community.robotics.abb.com/t/rs-2019-5-issues/9255 "2020-01-03T07:13:58Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Gpe](https://avatars.discourse-cdn.com/v4/letter/g/ce73a5/32.png) [@Gpe](https://tech-community.robotics.abb.com/u/Gpe)\
**Post date:** [January 3, 2020, 7:13am UTC](https://tech-community.robotics.abb.com/t/rs-2019-5-issues/9255/1 "2020-01-03T07:13:58Z")

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# Is there anyone with this issue ? Functional RS system with external axis does not work after restart of controller or RS, error message : RobotStudio .NET exception: Unexpectedly failed to calculate mechanism position.

Base exception: InvalidOperationException  
Unexpectedly failed to calculate mechanism position.  
at RobotStudio.Services.Controller.VcManager.CalculateMechanismPosition(RsIrc5Controller irc5ctrl, String mechUnitNames)  
at RobotStudio.Services.Controller.VcManager.IsBaseFrameUpdatedInternal(RsIrc5Controller irc5ctrl, Mechanism mechanism)  
at RobotStudio.Services.Controller.VcManager.IsBaseFrameUpdated(RsIrc5Controller irc5ctrl, Mechanism mechanism)  
at ABBInternal.Controller.StationVcMapper.HandleBaseFrameDifference(RsMechanicalUnit mechUnit, RsIrc5Controller irc5Controller)  
at ABBInternal.Controller.StationVcMapper.RemapVCMechanicalUnitToStation(MechUnitInfo vcMechUnitInfo, RsIrc5Controller irc5Controller, RobBaseFrameType vcBaseFrameType, Boolean bCheckBaseFrame, List`1 oldMechUnitList)  
at ABBInternal.Controller.StationVcMapper.d\_\_18.MoveNext()