# MacOS - Port failed to open - already in use?

**URL:** <https://forum.lightburnsoftware.com/t/macos-port-failed-to-open-already-in-use/108462>\
**Category:** GRBL\
**Tags:** usb-connection-mac, mac, longer-ray5, request, grbl\
**Created:** [August 24, 2023, 9:20am UTC](https://forum.lightburnsoftware.com/t/macos-port-failed-to-open-already-in-use/108462 "2023-08-24T09:20:45Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![EBS](https://forum.lightburnsoftware.com/letter_avatar_proxy/v4/letter/e/a587f6/32.png) [@EBS](https://forum.lightburnsoftware.com/u/EBS)\
**Post date:** [August 24, 2023, 9:20am UTC](https://forum.lightburnsoftware.com/t/macos-port-failed-to-open-already-in-use/108462/1 "2023-08-24T09:20:45Z")

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Hi there.

I am using LightBurn on MacOS Ventura V. 13.5.1 with a Longer Ray 5 laser.

From time to time, I have a problem with connecting the laser to my Mac and to LightBurn. The error msg “Port failed to open - already in use?” shows up and I can’t connect the laser.

I already tried:

- turning the laser off and on again while LightBurn was open
- turning the laser off and on again while LightBurn was closed and opened it afterwards
- closing and opening LightBurn before and after connecting the laser via USB cable
- I tried every port and I tested an USB C cable for the connection

Nothing works, always “Port failed to open - already in use?”

I testet it on Windows and it worked - but using a Windows PC is not an option because I won’t take my private laptop to work.

So, how do I connect the laser with LightBurn via my Mac?

 ![Bildschirmfoto 2023-08-24 um 11.16.13](https://forum.lightburnsoftware.com/uploads/default/original/3X/6/c/6c44cf31cbf7006b104252ec8812f4ee12cadec0.png)

Any help would be appreciated!

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**Author:** ![Saprevett](https://forum.lightburnsoftware.com/letter_avatar_proxy/v4/letter/s/ebca7d/32.png) [@Saprevett](https://forum.lightburnsoftware.com/u/Saprevett)\
**Post date:** [September 8, 2023, 12:47pm UTC](https://forum.lightburnsoftware.com/t/macos-port-failed-to-open-already-in-use/108462/2 "2023-09-08T12:47:40Z")

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I have problems with this also, both MacBook and M1 chip iMac, but I also have problems with the laser stopping and pausing mid engraving. Hope someone can help us!!!

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**Author:** ![system](https://forum.lightburnsoftware.com/user_avatar/forum.lightburnsoftware.com/system/32/64335_2.png) [@system](https://forum.lightburnsoftware.com/u/system)\
**Post date:** [October 8, 2023, 12:48pm UTC](https://forum.lightburnsoftware.com/t/macos-port-failed-to-open-already-in-use/108462/3 "2023-10-08T12:48:13Z")

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Closed on October 8, 2023, 12:48pm UTC

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