[Barrow4491]

C:\Users\JBA\Documents\Arduino\libraries\HTU21D/HTU21D.h:31:7: error: previous definition of 'class HTU21D'

I'm wondering why there is a backslash before the .h file.

I just compiled the package of werk and it compiles fine out of the box here. Could it be that you have some library twice or something like this.

Regards,
engolling

Werk / engolling
I have been trying to work the problem out an then finally decided to delete every file and download of anything to do with AQM II and start from scratch.
The file compiled first time as expected, an all i can put it down to is a recent upgrade of Windows 10 on my computer, because of the issue of no ongoing support for the previous version by Microsoft.
Thank you for your support and thoughts on the matter.
Regards
Jim