Have you ever received Insufficient Privileges error after trying to access some record. Or maybe one of your Salesforce users reported this problem?
Not everyone knows that Salesforce provides a handy feature that allows to check why specific user have access to some record (for standard or custom object). This only works if Sharing Settings are set to “Private” or “Public Read Only” (as sharing doesn’t make sense for “Public Read/Write”).
The best way is to use System Administrator profile (or any other profile with View All Data permission), go to specific record and click Sharing button (this works ony in classic UI, as Sharing button is not yet available in Lightning).
and then we see which groups, roles or users have access to this record.
When we click Expand List button, we can see all users.
If we have a user id and record id, we can allso easily view this page without going through those steps and go directly to following URL: