Thx for response.
Well, upgrade to 1.6.9 gave me different error message:
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x18
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x66
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x66
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x1e
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x06
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x98
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x98
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0xe6
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0xf8
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x06
downgrade to 1.6.6 gave me this:
avr-g++: error: missing filename after '-o'
exit status 1
Error compiling.
downgrade gave me the same error I had with 1.6.8
avrdude: no programmer has been specified on the command line or the config file
- Specify a programmer using the -c option and try again*
Some of these errors apear even when I try to upload the code with board not connected to USB so I guess it's the matter of some IDE setting 