how do I unhide an Excel document that I accidentally hid on my Mac?

renjk wrote:

that doesn't work.... I actually HID it using an icon in Excel as I thought I was hiding columns; instead I hid the entire document. It's still there in faded font but I can't open it.

It sounds like you hid the workbook. You can "see" the file in the Finder but you cannot open it. And it doesn't appear in the list of recently opened Excel files.

Open Excel (no workbook necessary, just open Excel). Then do Window > Unhide. You should get a list of hidden workbooks. Select the one you want to unhide, then click OK.

Did you go to File>Open Recent in the Excel menu?

renjk wrote:

that doesn't work.... I actually HID it using an icon in Excel as I thought I was hiding columns; instead I hid the entire document. It's still there in faded font but I can't open it.

Open a Finder window and press the Command + Shift + . (period) keys simultaneously. 

This shortcut will toggle the visibility of hidden files, which will appear with a semi-transparent or faded icon. Press the same shortcut again to hide them.