When opening a record, instead of the form loading you just see this message.
Open quote is expected for attribute "class" associated with an element type "i".
Can be seen after an upgrade.
A misconfigured Formatter (UI Macro) on the form can cause this issue. This has normally been seen with the OneSearch UI Macro downloaded from the Share or Store apps. This is a Third party application and not supported by ServiceNow support.
To resolve issues with the OneSearch not working please reach out to its creators or review comments for it on the Share or Stope App.
To resolve the immediate issue of the form not loading, you can follow these steps to disable and remove the macro.
Deactivate the Macro
1) Navigate to System UI > UI Macros.
2) Search for onesearch_widget and select the record.
3) AT the top of the form, click the here in "To edit this record click here." to change your scope to OneSearch.
4) Uncheck the Active box and save the record.
Remove the Macro once inactive.
1) Navigate to the record which was previously not working.
2) Right-click the form header and select Configure > Form Layout.
3) Remove the OneSearch item from the left list and click Save.
The Share version of OneSearch is no longer supported.