When we run Regular Expression in a file having more than 200 pages, sitself getting hanged and we need to end the task to continue the work in Indesign.
Can you please be very specific. Is your system hanging when you run Find/Change and use the GREP section?
Indesign go hanged when we work Regular Expression on a file more than 200 pages as it's works very well for the files having upto 200 odd pages
I have seen this problem when GREP expressions get complicated. If the formatting won't affect the flow of the text you can create duplicates of your styles with the GREP Styles removed. Apply those styles using Find/Change with formatting. Repeat to restore the GREP Styles when proofing or printing or preparing final artwork. Changing font, size, or style can affect the flow of the text. Changing colour or underlines wont.