Background
Working on a project that had some sort of upgrade from Sitecore 8.x to 9.3. I was tasked with porting over previously WFFM to Sitecore Forms. I got a local instance that was worked on before, so I just continued the process.
Quest Begins
Form items are present under "/sitecore/Forms" and I had no problems working with the sections and text fields ...etc.
However, I noticed that the Formbuilder was empty, and i really needed to work in FormBuilder to get that extra access to actions etc .. And thus began my quest to solve the case of the missing forms.
Clues To The Mystery
So as not to bore you with my process of elimination (which was very painful and arduous ), I will just cut straight to the obvious and useful clues.
Comparison To A Fresh Instance Of Sitecore
I installed a fresh instance of Sitecore 9.3 just to have a comparison to my working local instance. Nothing was out of the ordinary in terms of the Forms showing up and Formbuilder working as it should. So this ruled out any missing patches from Sitecore for bugs.
Solr Log Errors
Thanks to Solr's verbose logging, I was alerted to something going on with the master index:
Line 12238: 2021-09-22 16:16:34.547 ERROR (qtp952562199-22)
[ x:---_master_index] o.a.s.h.RequestHandlerBase org.apache.solr.common.SolrException:undefined field is_templateFinal Solution
The Solr logs entries was actually the clue that opened the door. Some quick googling, led me to a 2 year old entry in Sitecore Stack-exchange: here.
The solution to my mystery seemed to have been resolved by the #5 solution.
Apparently my configuration of Solr index was looking for a computed field which was incorrectly spelt.
In my "Sitecore.ContentSearch.Solr.DefaultIndexConfiguration" file at "C:\inetpub\wwwroot\your sitecore instance\App_Config\Sitecore\ContentSearch" the entry was:
<field fieldName="istemplate" returnType="bool">Sitecore.ContentSearch.ComputedFields.IsTemplate,Sitecore.ContentSearch</field>My instance of Solr was looking for "is_template". A quick renaming of this field, a rebuild of the master index and ... VOILA!! mystery solved.
Hope this helps!
