subl.exe "R:\@overlong_folder_name\X3XKS9EEKC7648YUFRJ1DNZM6S0HXLMR8TYX9DKK4MM67TP55UJ5M1CSSJ2AQO0N8NVZSJP2VHH6H4L6TARUFZBECMEFPEPWH1DGEQ32EEJVY0X50G0RUE6LFFULYOZMHDAY4T0Q6PJWOEZ78S1IV58IJD4EFF50S2E5ZQQ7RVBXO81G0PNTL6PC8U2J7JG7XIGQ1DKOO9LL0DE4VKMBZDX719FNBX6DF49BAMR8HA8KNQ\Sublime 3 lines.txt"
or
subl.exe "\\?\R:\@overlong_folder_name\X3XKS9EEKC7648YUFRJ1DNZM6S0HXLMR8TYX9DKK4MM67TP55UJ5M1CSSJ2AQO0N8NVZSJP2VHH6H4L6TARUFZBECMEFPEPWH1DGEQ32EEJVY0X50G0RUE6LFFULYOZMHDAY4T0Q6PJWOEZ78S1IV58IJD4EFF50S2E5ZQQ7RVBXO81G0PNTL6PC8U2J7JG7XIGQ1DKOO9LL0DE4VKMBZDX719FNBX6DF49BAMR8HA8KNQ\Sublime 3 lines.txt"
only open an empty file (while Sublime 3 lines.txt has (as the title says) 3 lines of text in it)…