Mapping local folder - no write access

Hi!

I`m trying to mount a local folder into an alpine docker image by using:

docker run -p 8080:8080 -v E:\myfolder\data_dir:/opt/data_dir:rw myapplication

I can access the files and read them as normal - however when I try to write something in that folder I get access denied. I have tried to figure out if this is the expected behaviour / safety. Or if this is just a rookie mistake.

I`ll be happy to read some more documentation regarding this. Thanks
Unfortunately I can not submitt the dockerfile