I've repeatedly used the Volume Creation Wizard to try to encrypt a usb flash drive. I'm using OSX 10.11.4 (El Capitan) and the latest VeraCrypt. I've been through the whole process 6 times, and every time I get to the end successfully, only to get this error when I try to mount: "hdiutil attach failed - no mountable file systems". It's formatted as OSX Extended with the scheme as GUID Partition Map. I don't need it to be compatible with PCs.
Comments: I was not able to reproduce this issue on my side using OSX 10.11.4 and a USB flash drive (16GB) formatted using GUID map. Did you choose quick formating or not in VeraCrypt? In order to see where the issue comes from, there is a simple test: encrypt the flash drive using VeraCrypt and this time choose FAT (choose quick format). Once finished, mount the drive using VeraCrypt and check that it working properly in OSX. Then, open OSX Disk utility, select the mounted VeraCrypt volume (not the disk) and then perform an erase to format it using OSX Extended. Does it mount when you follow this procedure?
Comments: I was not able to reproduce this issue on my side using OSX 10.11.4 and a USB flash drive (16GB) formatted using GUID map. Did you choose quick formating or not in VeraCrypt? In order to see where the issue comes from, there is a simple test: encrypt the flash drive using VeraCrypt and this time choose FAT (choose quick format). Once finished, mount the drive using VeraCrypt and check that it working properly in OSX. Then, open OSX Disk utility, select the mounted VeraCrypt volume (not the disk) and then perform an erase to format it using OSX Extended. Does it mount when you follow this procedure?