Unable to open file error

I am getting this error with Win10 Pro
I have protected folders features turned off in Win Defender
I see other *.dat files in that folder
any ideas?

2017-12-19 20:32:51 Unable to open file C:\Users\911\AppData\Roaming\Litecoin\blocks\blk00068.dat
2017-12-19 20:32:51 ERROR: WriteBlockToDisk: OpenBlockFile failed
2017-12-19 20:32:51 *** Failed to write block
2017-12-19 20:52:44 socket sending timeout: 1201s

encrypted disk?

Not encrypted disk
SSD 50% full

how many GB is 50% full?