Before you tell me I'm in the wrong forum, keep reading.
I was getting and error message when I tried to use the Onion Skin feature in Select and Mask. It said the feature was not available because of a program error. Not a lot to go on to fix it. I searched the forums and found a lot of people had the same problem...all unresolved or partially resolved or temporarily resolved. Then I found the Troubleshooting page with this comment:
"Reverting Photoshop’s preferences to their factory-fresh state can solve many issues (including program errors, strange tool/interface behavior, etc). See Restore preference files to default.".
I didn't like that statement because I don't know for sure what other preferences will be reset and how much of a pain its going to be to reset things to my liking.
Then I watched Julieanne Kost's video on resetting your preferences:
Following her direction, it looks like my problem is resolved, but now I have a new problem.
Julieanne asks that we create a new post and send you our corrupted preferences file so your engineers can figure out what went wrong. She sends you to feedback.photoshop.com where you can sign in with your regular Adobe password or make a new "Get Satisfaction" password. It tells you you're signed in, but the page where you describe your issue never recognizes either password.
Now I have a contribution that I can't attach to this post.
It's really annoying to have to spend so much time hunting for an answer and then having to fix the problem myself. It's worse when you are asked for feedback and are shut out from sharing it. I ought to charge Adobe for the two hours I spent hunting for an answer - that's $300 - Send me Starbucks cards or a prepaid Visa and we'll call it even.
Meanwhile, I've posted the corrupted prefs file here: Adobe Photoshop CC 2017 Prefs.psp - Google Drive so if you really want to work on the problem, you can go get the file yourself.
It would be a good idea to post this fix on all the unanswered Onion Skin feature problem posts.
Please test your software more - it would be worth it for customer satisfaction.
Annoyed in Austin
This is a user to user Forum, so you are not really addressing Adobe here, even though some Adobe employees thankfully have been dropping by.