Homepage Gauges are Disappearing
Several users have had issues with certain homepage gauges intermittently disappearing - usually upon first reload after logging in. This is due to a known issue with ServiceNow where gauges will not be displayed on homepages if they contain non-ASCII characters. These characters will sometimes appear in text fields like Short Description, Additional Comments, and Work Notes.
ASCII characters are essentially a catalog of commonly used English letters and numbers (learn more here.) Most non-ASCII characters input in ServiceNow come unintentionally, via inbound email from customers.
Non-ASCII characters will not break ticket forms or other reports - if you open your custom homepage gauge via the Reports > View/Run view, all data will appear. You'll be able to identify the non-ASCII characters because they will appear as a converted string. For example:
The screenshot below shows non-ASCII characters converted for view in ServiceNow in the Short Description of INC0155013. ServiceNow is interpreting the quotes used around runtime error as an html string. This is the piece that "breaks" when attempting to display these reports on gauges.
The easiest way to resolve this issue is to remove text fields from the reports that feed your custom homepage gauges. Additional Comments is the biggest offender, followed by Work Notes.
We have also seen some issues with Short Description, but it has not yet impacted any of the global homepage gauges. We will continue to display Short Description on global gauges so long it does not become an issue.
The root cause has to do with how ServiceNow itself is coded. ServiceNow is aware of this issue but has not provided any details or timeframe on addressing it. You can read ServiceNow's documentation of the error in the ServiceNow Knowledge Base.