Looks like you converted a monolithicFlat virtual hard disk to a monolithicSparse and with such a small SSD you should have converted it to twoGbMaxExtentSparse instead! 
Although do try now as you've not enough free space on the Host to do so until you remove the Virtual Disk-flat.vmdk-converttmp and Disk.vmdk-converttmp files, which were probably orphaned by running out of space on the Host. BTW don't delete those untill you make sure the new disk is working okay.
Going forward... the best case for twoGbMaxExtentSparse vs. monolithicSparse is with the latter you need the size of the disk in free space plus a bit more for overhead to remove Snapshots and with the former (twoGbMaxExtentSparse) just 2 GB plus a bit more for overhead. 
IMO a 256 GB SSD is to small to be using monolithic type disks!