I am using Windows 10 and Office 365. I have a short VBA procedure that saves a presentation both to its own folder and to Dropbox. In order to make this available to all PP presentations I have to make it into an add-in. I have checked that it runs correctly as a .pptm file, and I then saved it as a .ppam in the add-ins folder. It showed correctly in Powerpoiint in File | Options | Add-ins. I then went through Options to Manage | PowerPoint Add-ins, ticked the relevant box and clicked Load. All the relevant instructions that I can find say that it should now be showing on an Add-ins tab. In Options | Customize Ribbons I have ticked Add-ins. However, the Add-ins tab does not show on the ribbon. This applies to files from Trusted Locations, and I have even tried enabling all macros. Checking the File | Options | Add-ins I can see the add-in shown under the Active Application Add-ins heading.
Using the same procedure on another machine using Vista / Office 2007 the above actions work OK and show the Add-ins tab on the ribbon. Any advice please on how to get the Add-ins tab to show on the ribbon in Office 2016?