At 10:50 09 June 2020, s6 wrote:
Hi

I downloaded a flight from my Clearnav vario with IGC logger for the
first
time.

OLC says it is not a IGC file.

Advice are welcome to solve this problem.

Thank you.

Gilles

Hard to tell without seeing the .IGC file. Try opening the IGC file with a
text editor and posting the first 12 (or so) records here. The first line
should start with the letter "A".

Tim.