I’ve been pasting some information from some weblogs into Calc (the OpenOffice / LibreOffice Excel equivalent) and some version numbers like 1.5.30 got changed to dates. All the documentation pointed me towards changing the cell format to text. That only works if you type the numbers, not if you paste them. When you paste them the cell format get changed to number again. Read more for the solution…
One sollution would be to paste as unformatted text. Unfortunately this didn’t work for me as I couldn’t get the data to align (columns kept overflowing).
The solution I found was to set the Default style. Press F11, right click on Modify and change the format on the Numbers tab to text.
No matter how many explanations I read about how this behaviour is a Good Thing (TM) I still consider this type of behaviour brain dead and there should be a switch to disable automatic date formatting.