"Unable to Obtain Exclusive Access to this Record" Error When Editing a Candidate Record

When a User encounters an error that Salesforce was unable to obtain exclusive access to this record after editing and trying to save a Candidate record it is often due to Data Skew, which is having too many records associated with a single account.

Many orgs are set up with a single Dummy Account (Candidates) where all new Contact records are saved. If multiple Candidate records are edited at the same time by different Users they can all be trying to record new Activities on the same Account record, causing the error. Salesforce recommends no more than 10,000 child records owned by a single parent record.

To solve this, the org should utilize the Parsing Account Data Model which automatically limits the number of Candidate records per Account and creates new Accounts as needed.