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Balasubramani DhanapalBalasubramani Dhanapal 

How To Delete Master detail Field

HI All,
         I am Begginer of salesforce,I have  Create one Master field to One object(xxx) to another Object(yyyy).Now I dont want master Detail filed. So,How To Delete that master Field.??

Advance Thanks

Delete all the child records (also from recyle bin), then you can delete the relation ship field in the child object.
Also if you have any rollup summary fields in the parent  you have to delete those field from the parent.

you can access recycle bin by below url
https://<your instance>
Anoop yadavAnoop yadav
Do you have any Rollup Summery field on that object?
If yes, first delete that Rollup field and then try to delete the master detail field.
Akshay DeshmukhAkshay Deshmukh
change the field data type to "lookup" first. then delete that " lookup field".
This should solve your problem
Anil KamisettyAnil Kamisetty
Probably you should expand on what is your need. There are two options. Either you can delete the Master Detail relationship field (it shows up the Owner field on the child object automatically) or you can change the field data type (Master detail relatinship) on the child object to another type (say lookup) using the CHAGNE FIELD DATA TYPE option. If there are any dependant roll up summary fields using the master detail relationship, you would not see the Change Field Data type button. You need to delete the roll up summary field and then change the data type or delete the field itself.
Puspendra SinghPuspendra Singh

I have two custom objects A & C (connected usined Master Detail RelationShip), parent "A" which had a rollup summary field from Child "C". I wanted to drop child object, hence deleted the rollup summary from "A". But its still not allowing me to delete the child object. The message it is giving is "This custom object is summarized by a field in another object. Remove the usage and try again." However when I check the parent object, the rollup summary is already deleted. 
Can someone tell me what could be the possible reason for this?
Andrew Tietz 3Andrew Tietz 3
I have this exact same issue. Cannot delete the master/detail relationship because of a summary rollup field that no longer exists. 
Assunta OropalloAssunta Oropallo
Hi, I've got the same problem. This is the answer of Salesforce support to solve the issue:
1. Go to Setup (Classic)
2. Account (Your object)> Fields
3. Scroll down and click on "Deleted Fields"
4. Click erase beside your filed.
Hope that this may help you! :)
arun mohan 17arun mohan 17
Thanks Assunta Oropallo, that resolved my issue.
Musadul IslamMusadul Islam

Switch back to classic mode. Now, go to custom fields and relationships and click on deleted fields. now erase the deleted fields. This worked for me. 

for more-

prachi thaleprachi thale
Mark as best Answer if this one works.
Following worked for me.
  1. First Switch to salesforce Classic
  2. go to setup -> Build ->Create
  3. Objects->(your) custom object->Custom Fields & Relationships.If you have already deleted Rollup summary field Click on deleted fields
  4. Click on Deleted Fields ->Then Erase ->User-added image
  5. Check checkbox and press Delete button.
User-added image
  1. After this,Try to delete Master-Detail Again.
Hope This will work.
Tejas IngaleTejas Ingale
I have 2 objects in master details relationship, one is masterand one is details, Can I directly delete Master object(Having records as well as Rollup summary )?
Vijayakumar PerumalVijayakumar Perumal

Hi all, 

How to delete Master-lookup field in Salesforce Lightining,

Setup-->Object Manager-->Select which (Object ) inside of an Master-Lookup field -->Down Arrow-->Delete the field.,User-added image

If it has related roll-up summary field do following:

Go to Roll up summary created Object-->Fields & Relationship -->down arrow--> delete the filed Then after deleted 

SamePage Upper Right side have one Button called(Delete Field--> inside available rollup summary field click  Erace --> done.., User-added image