Robot fails with 'RPC server is unavailable' and keeps failing until restarted

We have a problem wherein Robot does not work again untill runtime is restarted even when we have variety of test data. The error in logs is 'RPC server is unavailable'.

Has anyone experienced this before?


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September 13, 2018 - 11:24pm

Please upload logging of this issue to the post. Also, if it works after Runtime is restarted, why doesn't it work the first time runtime is launched? What happens the first time runtime runs?

September 18, 2018 - 9:13pm

It works when we launch Runtime for the first time as well as when we restart Runtime. Problem is sometimes after ending in a failure, it continues to fail with the above error.

Have analysed the error cases, especially the error when it fails for the first time, as this could be the root cause for errors during subsequent runs. But, the error is different each time.

September 17, 2019 - 2:48am
Response to Mangesh Walhe

Any update or solution regarding the above issue. Am also facing the same issue now. Please update me.

System.Runtime.InteropServices.COMException (0x800706BA): The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)     at Microsoft.Office.Interop.Excel.ApplicationClass.Run(

September 17, 2019 - 3:38am
Response to BaskarN7

Hi @BaskarN7 -

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Vidyaranjan | Community Moderator | Pegasystems Inc.

September 17, 2019 - 8:13am
Response to BaskarN7

Dear Baskar,

The exception simply means that Microsoft Excel is not in a right state where it can be used.

The key is to check the runtime log for the penultimate execution on the Runtime where you are getting the exception. Once that root cause is resolved, the 'RPC Server.....' exception, which is simply occurring as a consequence would go.

Please check the logs. Revert in case you need any help. Would be happy to assist.

December 13, 2018 - 8:48pm

Recently, I have something which leads up to this issue.

If an automation fails while executing a remote procedure call (RPC), such as a VBA macro, we get an exception explicitly saying it. Unless we restart runtime, the subsequent automations which use Excel fail with the error as 'RPC server is unavailable'.

Need to find the root cause for why does it need restarting Runtime in order to be cured.

January 21, 2019 - 2:48am

Following this up, does anyone have any information regarding the points mentioned below?

  1. Does the product maintain a record of processes that are started/monitored using Adapters and Connectors while a solution is being loaded in Runtime and is being executed? 
  2. If yes, which I think is the most likely answer, where is it, and how is it managed, as in Update and removal.

Asking this, as I think there is no other way for the Runtime to know about previous failures.

Any input in this regard is highly appreciated.


Thank you,

Best regards,

Mangesh Walhe