If you load a CSV sheet and they are showing data (columns/rows) wrong use the Data > From Text (Import function).
A common example is when fractions get converted to dates.
- Click Next - Untick Tab - Tick Comma - Select the Column you want - Select the Text radio button instead of the General radio button - Next/Finish - Next/Finish
Another common example is when dates get converted to numbers. In this case:
- Select the whole Column - Right click and select Format Cells - Select the Number tab - Select the Category: Number - Then Select Custom - Enter the Date you want e.g. dd/mm/yyyy hh:ss:mm dd/mm/yyyy hh:mm:ss - Next/Finish - Next/Finish