Brand new Extreme USB 3.0 64 GB, unusable

can any one tell me why my sandisk 64 gb wireless is not recognised after i format it in mac

to exfat 32

is there any problem that i should know 

i am a mac user , will i need to format it in a pc for it to work again in my macpro 

I was having problem reading content and unable to backup the files this is becoming a little bad product in this sense 

Can any one help in this how to restore the sandisk 64gb wifi 

is there any limitation in the macpro for this pen drive