Can not produce a master from the timeline

I am not able to produce a master from the timeline due to all options being greyed out. First time this has ever happened. Tried adding a new option but to no avail. Your assistance would be greatly appreciated.

Thank you.

Did you actually select a timeline in the library or clicked on the timeline before share?

Sometime you see the timeline but it is not selected therefore it can't be exported/share.

Thanks for your input, however, this is the first time that I have encountered the problem while using FCP-X for many years. When the 'Produce a Master' is not greyed out it merely produces a master of a single clip. I badly need a composite master. Any other suggestions? Thanks

It’s possible the active selection is something like an event, which isn’t exportable. Select the project in the library and try Share from there.

When the 'Produce a Master' is not greyed out it merely produces a master of a single clip.

That really does suggest that you have not selected the Project but have selected a single Clip in the Browser. However, you say:

Thanks for your input, however, this is the first time that I have encountered the problem while using FCP-X for many years.

I did a search and found this on Apple's Final Cut Pro Support page:

If you see "This item cannot be shared while it is still referencing media on the camera", or Share menu options are dimmed
You may encounter the following when trying to share an item in Final Cut Pro:
"This item cannot be shared while it is still referencing media on the camera" alert.
Some clips have a camera icon on the bottom left-hand corner of the clip.
Share menu options are dimmed.
In your project, look for any clip with a camera icon . This icon indicates that the clip was never successfully imported into a Final Cut Pro library. Instead, the clip is located on a connected camera, on a memory card or in a camera archive. This could have occurred because a camera or other device was disconnected before the clip finished importing.
Use the browser search field to quickly find these clips.
In the Libraries sidebar, select any libraries, events or folders you want to search.
Click the Search button at  the top of the browser, and type missing in the search field. The browser shows all missing files. Any file located on a connected camera, on a memory card or in a camera archive appears in the browser with a camera icon . 
After you've located the affected clips, you'll need to reimport them from the original source to successfully share the item.

The original article is here:

support.apple.com/en-gb/HT207791

Thanks so very much for your detailed solutions for correcting this problem. I greatly appreciate it. I shall print out your response and commence correcting the problem.

Thanks very much for your information. I shall proceed with everyones input and remedy the problem.