I had similar effects with my first OSMC Pi3 installation.
I was unable to fix the partition of my MicroSD.
As mentioned before I had an old Ubuntu laptop with Gparted, deleted all partitions and created a new FAT32 partition.
Make a fresh installation
After that switch to a windows 10 box and used:
SD Card Formatter
Win32DiskImager Win32 Disk Imager download | SourceForge.net