I have found something that seems to of cured the problem for the minute.
Time will tell but it has worked initially.
Here goes:
Something new is found..
try this...
(1) Open a new worksheet
(2) Key in any words
(3) File -> Save As...
(4) Choose Format to "Excel 97-2004 & 5.0/95 Workbook". (You may not really need to choose this. It looks like the default format of "Save As..." in my mac.)
(5) After running "Save As...", it will run well this time. Now, just back to Excel and press "apple" + "s" (or just click save icon)
It will give you the same error message. (if it doesn't, just try another "apple"+"s". It will go hanging.)(If System Monitor is opened, you can find CPU utility goes 100%)
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Solution:
(1) Reopen the problem file
(2) File -> Save As
(3) Choose Format as to "Excel Workbook"
(4) After that, the problem goes away. And, I can enjoy "apple"+"s" now.
(5) I also switch the default format back to Workbook, too
Post your results whether it worked for you or not.
Fingers crossed
Cheers,
Rich