Hi guys, hope you are all fine.
I'm trying to create a master/detail field in a personalized object and I want to relate it to the object LEAD on the step 2.
When I try to find the LEAD on the list it does not show up. Is there any configuration that blocks this action? Is there any possibility to create this type of relation?
Thanks in advance!
Eric Praud (Activ8 Solar Energies) 
Forum Ambassador
Hi Tainara,
Unfortunately, this is not possible:
https://developer.salesforce.com/docs/atlas.en-us.api.meta/api/relationships_among_objects.htm
"You can define master-detail relationships between custom objects or between a custom object and a standard object. However, the standard object cannot be on the detail side of a relationship with a custom object. In addition, you cannot create a master-detail relationship in which the User or Lead objects are the master."
You can vote on this idea:
https://trailblazer.salesforce.com/ideaView?id=08730000000Bq50AAC
You would need to create a lookup relationship and use flows to recreate the roll up summary functionality:
https://www.aviralsfdc.com/post/rollup-using-lightning-flows
or
https://blog.certifycrm.com/create-a-roll-up-summary-with-flow/
If you have a developer handy, they can also do it with code.
Finally, you could also use this free package:
https://github.com/afawcett/declarative-lookup-rollup-summaries
If you use this package and have any questions, they have a chatter group here:
https://trailhead.salesforce.com/trailblazer-community/groups/0F9300000009O5p?tab=discussion
