In a blog written many years back Delete Custom Field, we shared items that will block and allow for field deletion.
Undelete field in Salesforce is also very simple, it will restore the field with data, but the admin need to note and perform a few actions as mentioned here:
A few items to note when the fields are in the recycle bin:
- You can see and open field detail from the object "Fields & Relationships" menu then click the "Deleted Fields" button
- The field API name will be changed with an additional _del, such as Test_Date__c --> Test_Date_del__c
- You can no longer query the field
- The field metadata will no longer exist
To check who and when delete the custom field is deleted, check the "View Setup Audit Trail", the action should start with "Deleted custom field "