macbook pro not recognizing available macos 26

Sorry, we cannot help with Beta issues here. If you are a registered developer, you can ask for help in the developer specific forums you have access to. Beta | Apple Developer Forums

Otherwise, you are on your own with any issues you encounter including installation. If you are going to be running a developer beta that is bound to to haver many issues, some possibly device breaking you should be able to figure it out on your own.

Apple Beta Software Program

Is the public beta software confidential?

Yes, the public beta software is Apple confidential information. Don’t install the public beta software on any systems you don’t directly control or that you share with others. Don’t blog, post screen shots, tweet, or publicly post information about the public beta software, and don’t discuss the public beta software with or demonstrate it to others who are not in the Apple Beta Software Program. If Apple has publicly disclosed technical information about the public beta software, it is no longer considered confidential.

Read our Terms for full details

 No Support and Maintenance; Future Products. During your participation in the Beta Program or in a particular seed, Apple is not obligated to provide you with any maintenance, technical or other support for the Pre-Release Software. If, at Apple’s option, such support is provided, it will be provided in addition to your normal warranty coverage for your computer and/or device. You agree to abide by any support rules and policies that Apple provides to you in order to receive such support. You acknowledge that Apple has no express or implied obligation to announce or make available a commercial version of the Pre-Release Software to anyone in the future. Should a commercial version be made available, it may have features or functionality that are different from those found in the Pre-Release Software licensed hereunder.

The reason for that is that macOS 26 Is NOT available for download, or even for Public Beta testing.

At this writing, the only ones who have access to the early Beta version is Developers, especially members of the Apple Registered Developer Program. This access comes with warnings that the current Beta versions are NOT FOR PRODUCTION, and may have unsolved Bugs and crash frequently. In general, "regular folks" do not want to get in on that. I recommend you wait for the Stable Release and you will dodge a mountain of abuse.

Some Trade Press have been able to look at early running demo versions. Their writing ANYTHING in detail (except Gross overall impressions about it) is strictly prohibited under the non-disclosure agreements they signed to get access to the software.

Developers, especially of Third-party software, need access to early Beta version to test their own software against candidate MacOS version that might be released sometime soon. They can NOT afford to wait until release-day to find things that will derail their products.

EDIT: Phil0124 post was not visible to me when I started composing. Nothing I said should be read as trying to diminish what they posted above.

The Software Update menu in System Settings is for incremental updates - i.e. 15.4 to 15.5. To install a major new version, you need to download the installer. However, as others have pointed out, Tahoe is only in developer beta right now and not available to the general public. If you are in the developer program, I’d imagine the installer is available on the developer site, but you’d have to look there as these are general forums and many here are not developers.