# Unable to start node-red after installing modbus sample code **URL:** \ **Category:** General\ **Created:** [9 May 2020 21:42 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393 "2020-05-09T21:42:21Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Zaza](https://avatars.discourse-cdn.com/v4/letter/z/e19b73/32.png) [@Zaza](https://discourse.nodered.org/u/Zaza)\ **Post date:** [9 May 2020 21:42 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/1 "2020-05-09T21:42:21Z")
Hi all, I recently copied the codes below related to modebus master and slave. Node red is not starting, and I am getting the error below. How do I go about solving or clearing the error? 9 May 21:46:27 - [info] Starting flows 9 May 21:46:27 - [error] [function:Pump 1 simulator] SyntaxError: Unexpected token ) 9 May 21:46:27 - [info] Started flows 9 May 21:46:27 - [red] Uncaught Exception: 9 May 21:46:27 - Error: listen EADDRINUSE: address already in use 0.0.0.0:10502 at Server.setupListenHandle [as \_listen2] (net.js:1280:14) at listenInCluster (net.js:1328:12) at doListen (net.js:1461:7) at process.\_tickCallback (internal/process/next\_tick.js:63:19) ---
**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\ **Post date:** [9 May 2020 21:49 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/2 "2020-05-09T21:49:10Z")
Firstly, no node should crash node-red, please raise an issue in the GitHub repo. Next, start node-red in safe mode, edit your flow then deploy. Search the forum, internet or read the docs for how to start safe mode. ---
**Author:** ![Zaza](https://avatars.discourse-cdn.com/v4/letter/z/e19b73/32.png) [@Zaza](https://discourse.nodered.org/u/Zaza)\ **Post date:** [10 May 2020 08:25 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/3 "2020-05-10T08:25:39Z")
Thank you Steve. I started in safe mode. I made the necessary changes, then deployed. Problem solved. Thanks again for your help. ---
**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\ **Post date:** [10 May 2020 08:27 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/4 "2020-05-10T08:27:13Z")
No problem. Did you raise an issue on the repo? Would be good for all future users for this to be fixed. ---
**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\ **Post date:** [10 May 2020 08:28 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/5 "2020-05-10T08:28:29Z")
It's a known issue. I don't think you can run both slave and master as they can't both "grab" the port. ---
**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\ **Post date:** [10 May 2020 08:34 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/6 "2020-05-10T08:34:27Z")
Cheers. Then perhaps @Zaza should leave a "me too" type of comment to add some weight behind it & let the Dev know it's not a one off? ---
**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\ **Post date:** [10 May 2020 09:03 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/7 "2020-05-10T09:03:09Z")
yeah - like shouting at devs really motivates them 😉 ---
**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\ **Post date:** [10 May 2020 09:16 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/8 "2020-05-10T09:16:25Z")
No of course not but if the dev believes it to be a one off concern - they might think its the users environment & not put too much time or thought into it. but if all users at least +1 or "me too" an issue (and the dev gives a monkeys) then it might re-order priorities. PS, I know you know what i mean 😉 ---
**Author:** ![Zaza](https://avatars.discourse-cdn.com/v4/letter/z/e19b73/32.png) [@Zaza](https://discourse.nodered.org/u/Zaza)\ **Post date:** [10 May 2020 09:40 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/9 "2020-05-10T09:40:08Z")
Yes, I raised it in the GitHub repo. I hope that someone will take note. ---
**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\ **Post date:** [10 May 2020 09:58 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/10 "2020-05-10T09:58:39Z")
Yes I know what you mean. But a +1 without any additional help/context/diagnostic is not moving things forwards. ---
**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\ **Post date:** [24 May 2020 09:58 UTC](https://discourse.nodered.org/t/unable-to-start-node-red-after-installing-modbus-sample-code/26393/11 "2020-05-24T09:58:48Z")
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