One of the new, exciting features of Sitecore 9 is the new forms module - a long-overdue replacement for Web Forms for Marketers!

So, on a rainy, Saturday evening, I sat down to finally play with this magical, new module!  I clicked on this cute little button on the launchpad:

Then, I clicked on the Create button in powerful ways to start a new, magical form.

I created a simple form and clicked Save.

It saved successfully! YAY!

I then navigated to Experience Editor to put my new form on a page, but realized I'd forgotten a necessary field...on my simple, test form.  It was quite a crucial field.

So from the Launchpad, I clicked on that cute little Forms button again to edit my Simple Powerful Form, but I only found this:

OH NOES!  WHERE IS MY SIMPLE POWERFUL FORM???

A quick check of the console of the browser showed that there was an error loading the page.

Cannot initialize module: Database Name.

I also saw these errors in the logs:

20:50:22 WARN Cannot resolve the scope because the item set is empty.

So naturally, I went to the source of all Forms knowledge in Sitecore - Kamruz Jaman - on Slack.  He suggested rebuilding the master index, so I gave that a try.  After about 49323ms later, I clicked on that cute little Forms button on the launchpad again and:

Turns out, this is a known issue in the Initial Release of Sitecore 9, but that shouldn't hold you back from submitting a support ticket.  The more people holler about this bug, the quicker it will get fixed.  And yes, it's a bug.  You shouldn't need to manually go rebuild the master index just to see your form.

UPDATE: Thanks to Gert, I have been informed that this question had been asked and answered 3 days prior to my post on StackExchange, so I'll post that link here as well!

https://sitecore.stackexchange.com/questions/8518/why-i-cant-see-my-forms-templates-in-the-sitecore-forms-application

Happy Sitecore trails, my friend!