Yes. Excel cells are set to a "General" format that, by default, tries to guess the type of data the cell should be from its content. A date looking entry gets

Yes. Excel cells are set to a "General" format that, by default, tries to guess the type of data the cell should be from its content. A date looking entry gets converted to a date type. A number looking string to a number (so 5.80 --> 5.8, very annoying since I believe in significant digits) When you import cvs data, for example, the default import format is "General" so date looking strings will be changed to a date format. This can be avoided by importing the file and choosing to import the data as "Text". People having these data corruption problems forgot to do that. It's "user error" except that there is no way to set the default import to import as "Text" (as far as I know), so one has to remember to do the three step "Text" import every time instead of the default one step "General" import.