Can't break the endless "Calculate"

Hello,

My spreadsheet, suddenly runs in an endless "Calculate" mode.
The workbook has many macros and I don't know which one is causing this.
I am trying to break it with Ctrl + break, but it won't break.

1. How can I break the loop ?
2. What is procedure to track down the code which causes this?

Could you please advise?
Thanks

What is "endless"? What is the longest it has run?

I can think of two possibilities.

1. You are in an infinite loop. You must identify any indefinite loops (Do While or Do Until) and determine which one is stuck. You can put debug.print statements in every loop and watch the Immediate Window. You can insert DoEvents in every loop, which will allow a interrupt and CTRL+BREAK should work. (It should work anyway.)
2. You are doing a massive amount of updates that keep triggering automatic calculations. You can disable automatic calculations at the beginning of the macro and re-enable at the end.

If you do not have private data in your file, attach it here and we can review your code.