Unless my issue has a different source it has not been solved on 11 February 2020. I had several time blank boxes with unresponsive searchUI.exe this month. Also Edge Chromium sometimes shuts down unexpectedly after several tabs were open, I am now using Firefox when doing online banking (safer). I deleted windows.edb and that helped for the time being. One tabloid pointed to "integration of Cortana with the Bing search engine" to be the cause. I have Cortana disabled in Search (value 0 in the registry) maybe that is making my system unstable?
Here is the error after Search becomes unresponsive (blank box):
Log Name: System
Source: Service Control Manager
Date: 18/05/2020 8:37:58 pm
Event ID: 7031
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: Acer-Aspire-5
The Windows Search service terminated unexpectedly. It has done this 1 time(s). The following corrective action will be taken in 30000 milliseconds: Restart the service.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<Provider Name="Service Control Manager" Guid="{555908d1-a6d7-4695-8e1e-26931d2012f4}" EventSourceName="Service Control Manager" />
<EventID Qualifiers="49152">7031</EventID>
<TimeCreated SystemTime="2020-05-18T12:37:58.001721500Z" />
<Correlation />
<Execution ProcessID="844" ThreadID="7660" />
<Security />
<Data Name="param1">Windows Search</Data>
<Data Name="param2">1</Data>
<Data Name="param3">30000</Data>
<Data Name="param4">1</Data>
<Data Name="param5">Restart the service</Data>