Cells Display As #######

I copied text from a large volume of different sources into three spreadsheets. When my webmaster went to import the data from a smaller test excerpt, he made sure that the column with the text in it had the cell formatting changed from "general" to "text".

Once this formatting change was made, some but not all, rows in the spreadsheet instead of displaying the text displayed "########". Other rows were fine.

I have tried using the TRIM command and the CLEAN command on one of the cells in order to see if this clears up the problem. But, my cell still displays as "####". For a smaller, sample spreadsheet, my webmaster fixed the problem by manually retyping the text.

I have too much text in the three spreadsheets to retype this all. Plus, when I tried retyping one sample cell, after having cleared it, I still got the "###" displayed as soon as I entered the "." at the end of the first sentence. But, other cells have periods ending sentences with no problems.

I do not know if there are additional hidden codes or some other problem in the text itself.

Does someone know of a tool or tools to clean text data so it is validly formatted as text? Or, if I should use a series of commands, I want to do them in the right order and do all of them so I don't lose any data. I have three spreadsheets each in excess of 1,000 rows, so corrupting the text is one concern and not having to retype text is the other.