[pielud]

Any numbers with leading zeroes, i.e. 0000123, excel will interpret as the integer 123 even if you change the column format to "text". It's infuriating.

The only way I found to get around this was to open a new workbook, change the column type to "text" and then paste the data in. I believe this was excel 2010 on windows.

[azadder]

You can add an apostrophe before the leading zeros, and the cell will keep the zeros and still be a number type.