dave-in-nj:
if you know there is a problem in your code, then the only way to help is to show the experts your code.let's try another way.
save-as to a new file
delete everything except the BME and SD card stuff.you don't need to show anything but temp/pressure
no special values or calculations, and change all the names to temperature humidity and pressure
so things like refrigerator_temperature or whatever don't give away your secrets.you should be able to read the temperature of ONE BME without I2C conflict.
you should be able to write temperature and pressure and if you have an RTC, the time and date.as for the serial, when you open your serial monitor, the lower right shows the speed the monitor expects to receive. that has to match what your sketch sets as the speed of the output.
and you do know that you cannot format your SD in your PC, right ? it has to be formatted by a special program that does not add operating system junk.
this should be one of the first things any instructable tells you about using an SD with a micro.get the BMP and SD to work, then add the next thing.....
ok i will show my full code, i mean top to bottom