Apple File System (APFS) introduced with High Sierra is faster and better for a SSD but not fully compatible with CS6.
Fortunately it's possible to install macOS High Sierra without APFS conversion:
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/startosinstall --converttoapfs NO
This will force installer to bypass APFS conversion. High Sierra will run on HFS+.
I didn't find any errors so far!
I have photoshop cs6 13.0.6 running on High Sierra 10.13.3 with the Apple File System (APFS) and mostly it works fine, certainly usable.
What problems were you having that led you to switch to HFS+?