Excel hangs on opening file
 

I have a excel spreadsheet that has been created by a 3rd party application.
The file is 23MB in size and contains 33,500 lines. It hangs every time I
try to open it.
I save the same file to .txt and then opened and saved it as excel. File is
much smaller (8MB) and opens with no difficulty. Any suggestions?
There are other excel files created using the same 3rd party app that open
fine.
Dee