My MacBook Pro not detecting an external monitor using Adapter Type-c

Is this your Display?

https://en.wikipedia.org/wiki/Apple_Thunderbolt_Display

If it is, then it is a true Thunderbolt 3 cable is needed.

USB-C is NOT Thunderbolt, it can be Thunderbolt, or just USB, it can be USB and DisplayPort, it can be 5GHz, it can be 10GHz, it can be 20GHz, it can be 40GHz, but the cable has to explicitly support that features.

As the above link is to a real Thunderbolt 3 monitor, it needs a real Thunderbolt 3 cable.

If you really have a Thunderbolt 3 cable, and not adapters in the middle, it should work.

If you have difficulties, then try an SMC reset

Mac SMC Reset: hhttps://support.apple.com/en-us/HT201295

If you have another Mac with Thunderbolt ports available, try the monitor with that Mac. If you have other Thunderbolt 3 cables, try one of those.

A Thunderbolt cable should have the lightening bolt icon with the down pointing arrow on the connector, as shown in the following image of an Apple Thunderbolt cable:

That the cable you are using fits into a USB-C socket is necessary, but is not sufficient. You specifically need a Thunderbolt cable here. A Thunderbolt cable which should usually have a lightning bolt on it.

… Use USB-C cables with Mac - Apple Support

… About the Apple Thunderbolt 3 (USB-C) Cable - Apple Support (note the lightning logos on the connectors in the image)

Do you have this cable?

Ensure the USB-C cable in use is a Thunderbolt cable.

There are various sorts of cables available with USB-C connectors, and the cheapest ones are useful only for charging and for low-speed USB connections.

Most USB-C Thunderbolt cables will have a thunderbolt ⚡️ icon on the connector.

Thunderbolt cables are more expensive, but work with most connections.

Anker offers a one-meter USB-C to USB-C Thunderbolt 3.0 Cable, for instance. As does Apple.

MEDSAMY wrote:

i use a genuine Cable( Thunderbolt to type c )

USB-C is a connector spec. It doesn’t have any direct relationship to the protocols used via the connector. All sorts of stuff runs via USB-C connectors. DP, PD, TB, various USB speeds, HDMI, etc. Variously protocols with different cables, and different cable requirements. And the “default” cables that Apple sells for USB-C connectors are not Thunderbolt. They’re low-speed USB (e.g. USB 2.0) and USB PD cables.

…The Monitors With Mini Dipslay Cable Still Work With an adapter or not ?

DisplayPort is a subset of Thunderbolt. And I would not expect to use DisplayPort with a Thunderbolt display.

HELP5499 wrote:

My external monitor for my Mac book was working now won’t

Please start your own thread (the Ask A Question link in the upper right), and please include details of which MacBook, MacBook Pro, or MacBook Air and its year (see 🍎 > About This Mac for that info), and which model of monitor, and which cable is in use. (Otherwise, these mixed threads just get me confused.)

Unless you have a USB-C Thunderbolt connection that is, as was described above, and if you do have that configuration and do have a USB-C Thunderbolt connection, then ensure you have a Thunderbolt cable.

I’m following your nick, so I’ll see and respond to the new post.

My external monitor for my Mac book was working now won’t