You have a Lead with status Converted.This Lead is not editable whereas other Leads with the same status Converted are editable.
Reproducing the Issue
Go to Sales workcenter.
- Go to Leads view.
- Open the Lead 123 with status Converted(where 123 is Lead ID).
- Lead 123 is not editable.
- Now Open another Lead 345 with status Converted(where 345 is Lead ID).
- Lead 345 is editable.
This is one of a case where the follow up Opportunity for a 'Converted' Lead has been deleted . So, the system treats it as an Account and Contact conversion, which is true because while converting to an Opportunity, the inactive Account and Contact was converted to an Active Account and Contact.
Since, there are no follow-up Opportunities, the conversion type is treated as 'Convert to Account & Contact' and we don't allow editing a Lead for such a conversion type.
As for Lead 345, it is editable because the number of Lead to Opportunity conversion allowed is set to a number 'x' in Leads fine-tuning and since a follow-up opportunity exists for this Lead, the conversion type is 'Convert to Opportunity'.
If you want to delete Lead 123 , you can do so using Data Workbench.
Convert to Account and Contact,Opportunity , KBA , lead , converted , LOD-CRM-LM , Lead Management , Problem