Lightning feature is removed from sandbox after refresh from Production org which uses Person Accounts
|Knowledge Article Number||000231236|
|Description||Users will notice that they no longer have the Lightning feature functionality available in their sandbox, after a refresh.|
|Resolution||The user can log a case with Salesforce support to have the Lightning Experience feature re-enabled by a Tier 3 engineer.
As there are currently incompatibilities between the Lightning Experience and Person Accounts, the Lightning Experience is not available in Production orgs which have Person Accounts enabled. (See this related article for more information: https://help.salesforce.com/apex/HTViewSolution?urlname=Lightning-Experience-compatibility-with-Person-Accounts&language=en_US )
When a sandbox is refreshed from one of these Production orgs with Person Accounts and no Lightning Experience, the same settings are carried over. At this time, the user will need to request a manual re-enabling of the Lightning Experience feature for the affected sandbox.