# Serial ports disappear after years of working reliably

**URL:** <https://discourse.processing.org/t/serial-ports-disappear-after-years-of-working-reliably/49236>\
**Category:** Electronics (Arduino, etc.)\
**Created:** [August 21, 2026, 8:58pm UTC](https://discourse.processing.org/t/serial-ports-disappear-after-years-of-working-reliably/49236 "2026-08-21T20:58:07Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Craig](https://avatars.discourse-cdn.com/v4/letter/c/ed8c4c/32.png) [@Craig](https://discourse.processing.org/u/Craig)\
**Post date:** [August 21, 2026, 8:58pm UTC](https://discourse.processing.org/t/serial-ports-disappear-after-years-of-working-reliably/49236/1 "2026-08-21T20:58:07Z")

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I have several projects that have been using the Serial library reliably for years. Recently, on all of my computers (using Macintoshes) the /dev/cu.usbserial-XXXX port has disappeared. The Bluetooth ports are still there when listed. This puts me dead in the water. They also are not listed in Terminal. Help would be appreciated, because I’m in a pickle.

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**Author:** ![svan](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@svan](https://discourse.processing.org/u/svan)\
**Post date:** [August 21, 2026, 9:37pm UTC](https://discourse.processing.org/t/serial-ports-disappear-after-years-of-working-reliably/49236/2 "2026-08-21T21:37:20Z")

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> [@Craig](#):
>
> the /dev/cu.usbserial-XXXX port has disappeared.

Do you have some device plugged into your usb port(s)? They only show up in Terminal output when you are using them on my MacOS system (M4 Tahoe 26.5).

You should see all of them listed when you type this into Terminal:

`ls /dev/{tty,cu}.*`

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<div class="post-metadata">

**Author:** ![Craig](https://avatars.discourse-cdn.com/v4/letter/c/ed8c4c/32.png) [@Craig](https://discourse.processing.org/u/Craig)\
**Post date:** [August 22, 2026, 5:40pm UTC](https://discourse.processing.org/t/serial-ports-disappear-after-years-of-working-reliably/49236/3 "2026-08-22T17:40:25Z")

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Thanks, your information go me to the solution. I