Dates formatted as GENERAL

[RolandPulse]

I have a large spreadsheet (downloaded from bank statements), where the first column has the dates, formatted like 29.05.2020.

It is formatted as GENERAL.

When I change the cell format to DATE, it does not recognize it as a date.

When I use =DATEVALUE(cellnumber), it shows #VALUE!

How do I convert the column to dates (so I can sort by date) ?

Thanks

[#2]

@RolandPulse 

Most probably you have texts in the column. You may try to select it, Data->Text to Columns and on the third step of the wizard select Date and DMY. Be sure column is not split.