trigger UpdateUser on CustomObject__c(before insert) {
 list<CustomObject__c> clist = new list<CustomObject__c>();
 String[]uId = new String[]{};
 for(CustomObject__c e: trigger.new){
    uId.add(e.MID__c);
   }
 
 map<Id,User> umap  = new map<Id,User>([Select u.Emp_ID__c, u.Id From User u where u.Emp_ID__c in:uId]);
 
 
 map<String,Id> umap2 = new map<String,Id>();
 
 for(User u:umap.values()){
     umap2.put(u.Emp_ID__c,u.Id);
 }
 
 
  for(CustomObject__c e: trigger.new){
    if(umap2.containsKey(e.MID__c)){
       
          e.User__c = umap2.get(e.MID__c);
         }
         else
         {
             clist.add(e);
         }
  }
 Map<String, String> mid_cid = new Map<String, String>();
 Map<String, CustomObject__c> mid_obj = new Map<String, CustomObject__c>();
 Map<String, Account> cid_account = new Map<String, Account>();
 List<User> newUserList = new List<User>();
 
  for(CustomObject__ce:clist){
      mid_cid.put(e.mid__c,e.Cost_Center__c);
      mid_obj.put(e.mid__c,e);
  }

  List<Account> alist = [Select a.Role_ID__c, a.Name, a.Id, a.Cost_Center__c From Account a where a.Cost_Center__c in : mid_cid.values()];

  for(Account acc:alist){
      cid_account.put(acc.Cost_Center__c,acc);
  }


  for(CustomObject__c e:clist){
 
      String emailAddr =e.Email_Address__c;
      
      User u = new User(FirstName=e.First_Name__c,
                        LastName=e.Last_Name__c,
                        Alias=e.First_Name__c.substring(0,1)+e.Last_Name__c.substring(0,3),
                        email= e.Email_Address__c,
                        UserName=e.Email_Address__c,
                        CommunityNickname= emailAddr.split('@')[0],
                        ProfileId='00eQ0000000M59D',
                       UserRoleId = cid_account.get(e.Cost_Center__c).Role_ID__c, // if i comment this line then its working
                       Branch__c = cid_account.get(e.Cost_Center__c).Name,
                       languagelocalekey='en_US',
                     localesidkey='en_US',
                     timezonesidkey='America/New_York',
                     emailencodingkey='UTF-8',
                     Emp_ID__c= e.MID__c);
    newUserList.add(u);
    }
  insert newUserList;
}

when iam trying to create new custom object record.iam getting following error.

 Error: Invalid Data.
Review all error messages below to correct your data.
Apex trigger UpdateUser caused an unexpected exception, contact your administrator: UpdateUser: execution of BeforeInsert caused by: System.DmlException: Insert failed. First exception on row 0; first error: MIXED_DML_OPERATION, DML operation on setup object is not permitted after you have updated a non-setup object (or vice versa): User, original object:  CustomObject__c: []: Trigger.UpdateUser: line 70, column 1