Can't hide my PERSONAL.xlsb workbook

Have you checked that the file isn't actually read-only through Windows? In Win7 you can find it here: C:\Users\AppData\Roaming\Microsoft\Excel\XLSTART\Personal.xlsb (if you don't have a 'Roaming' folder, replace that with 'Local'). Right-click the file and check if the 'Read-only' tick-box is ticked. If it is, un-tick it.

If that's not the problem, are you trying to open a second instance of Excel? If so, the first instance will 'lock' Personal.xlsb so it is then read-only for the second.

Don't tick the 'Hidden' box through Windows - that's a Windows file attribute and nothing to do with Excel.

First off, run 'Task Manager' and check that there aren't any other instances of Excel running somehow (check 'Processes', not just Programs) - sometimes Excel doesn't shut itself down properly and continues running in the background - though if you've restarted the computer this is very unlikely. If there is an extra instance running, use 'End process' to stop it.

Assuming that the above doesn't apply:

Do you have anything saved in the Personal.xlsb workbook (personal macros, etc)?
(1) If not, then the easiest thing to do is to close Excel then delete the Personal.xlsb file. Now open Excel again - Excel will automatically re-create it for you and it should automatically be hidden too.
(2) If you're not sure, close Excel then rename Personal.xlsb to something else (e.g. Personal.xlsb-old). Now open Excel again - as for (1) above, it should be automatically re-created and hidden. Now check that everything which should be working (any customisations, etc which you use) is still working.
(3) If you know that you do have macros in the Personal.xlsb workbook, then try copying all of them to another workbook (file type .xlsm or .xlsb), then close Excel, rename Personal.xlsb (as in (2) above), then open Excel again and copy the macros back to the newly-created Personal.xlsb.

Hopefully one of those options will work for you.

Sorry, I should have mentioned in the previous post - it will only re-create the file when you do something which needs it, like recording a macro. If you know how to do this, ignore the rest of this post - if not, read on...

To record a macro, click the 'Record Macro' button near the bottom left of Excel (see pic below). This will open a window where you should select 'Personal Macro Workbook' (see second pic below). Name the macro whatever you want (or leave it as 'Macro1' and click 'OK'. Then do something - type something in a cell, or select one cell then another. Then click the 'Stop' button which has replaced the Record Macro button (see third pic below).
Excel should now have created Personal.xlsb (you might have to exit Excel first, I'm not 100% sure) and it should be hidden by default.

The macro won't do anything harmful, but if you want to get rid of it (don't worry, that won't then delete Personal.xlsb) then press Alt-F11 to open the VBA Editor which looks like the last pic below. Look on the left hand side and you'll see what looks like a folder tree, with one labelled 'VBAProject (PERSONAL.XLSB)'. Under this, you'll see 'Modules' and inside that (double-click it) you'll find 'Module1' - double-click that (or right-click and choose 'View Code') and you'll see the code for the macro you just recorded. You can delete it by deleting everything from 'Sub Macro1()' to 'End Sub', or delete the entire module by right-clicking 'Module1' and selecting 'Remove Module1' - you'll get asked if you want to export it first - just select 'No'.

If I'm right, that should do it - fingers crossed...

Here are the pics:

Record Macro button:

Record macro button.jpg

Record Macro window:

Record macro window.jpg

Stop Macro Recording button:

Record macro button now stop.jpg

VBA Editor:

Record macro VBA result.jpg