PAN-Denmark,
What tool are you reformatting the microSD card with? It needs a 'Full Overwrite' reformat with 'Size Adjustment' 'ON', which is best achieved by using the SDFormatter Tool.
Alternatively download a fresh copy of the software from
https://pilotaware.lode.co.uk and copy the content of the download straight into the root (top level - i.e.
not inside a folder) of a brand new microSD card, which usually won't require formatting.
Please let us know how you get on, or if you need any further help.
Best Regards
Peter