If I right click on a cell in Excel and then click 'Link' I then get the option to select a sheet in the same excel document that I can link to.
For some reason, one sheet is missing. What causes this and how can it be fixed?

You will see that the 'UpHighonRVOL' Tab is missing from the options list.

see pics below.

options-excel.jpg

scrnshot_tabs.jpg