InfoPath form, rich text fields, "There was a form postback error" InvalidOperationException, There has been an error while processing the form

Question

Using InfoPath 2013 browser enabled form.
I am getting the above error on ALL Infopath Designed Rich Text fields, where the "Cannot be blank" attribute is set.
To reproduce it, I create a custom list and custom list form with InfoPath 2013. I add 2 Rich Text fields and enable "cannot be blank". To raise the error, I put some data in the RT field. Skip to another field (so focus is changed and a postback
occurs), then back to original field to delete the contents (to raise the validation).
I originally thought it was associated with the HTMLCHKR.DLL not being registered (and I have re-registered it just in case), but the exception I get from the ULS logs reads (it is from a list AFTER I have re-registered the DLL):
There was a form postback error. (User: 0#.w|myDomain\jc, Form Name: Template, IP: , Request: h t t p ://MyWebApp/MySite/Lists/rtAfterHtmlCHkrReg/Item/newifs.aspx?List=2212ff41-77b4-445b-931b-d7e538c9da91&Source=h t t p://MyWebApp/MySite/Lists/rtAfterHtmlCHkrReg/AllItems.aspx&RootFolder=&Web=3db49106-bdca-47bb-b4cd-a549d2d86aa7,
Form ID: urn:schemas-microsoft-com:office:infopath:list:-AutoGen-2015-01-16T21:51:48:853Z, Type: InvalidOperationException, Exception Message: No content generated as the result of the operation.) 8cc5e09c-3665-903b-575a-faaac506c40a
I noticed that errors associated with the HTMLCHKR.DLL not being registered would have some sort of COM exception (example: TYPE_E_LIBNOTREGISTERED or REGDB_E_CLASSNOTREG)
I also should mention that this problem started happening about 3 weeks ago. We have extended the web application to handle HTTPS on the intranet zone (we had a reverse proxy project that did not eventuate) - would that cause something? How can I do further
checking?

Answer 1

Hi,
I have done a test in my SharePoint, and I met the same issue with you.
I created a custom list and custom list form with InfoPath 2013. I added 2 Rich Text fields and enabled "cannot be blank".  I put some content in the RT field, then delete the contents, I got the error message:"there has been an
error while processing the form."
Here is a similar post said that executing the command: regsvr32 "C:\Program Files\Common Files\Microsoft Shared\
OFFICE14\htmlchkr.dll" will solve the issue.
https://social.msdn.microsoft.com/Forums/en-US/eb2e0f6e-c8e4-4e92-ac5e-a09d72759eda/rich-text-field-error-in-webform?forum=sharepointcustomizationprevious
But I just disabled "cannot be blank", and it solved the issue.
Best Regards,
Lisa Chen
Lisa Chen
TechNet Community Support