diff --git a/app/user.go b/app/user.go
index c10d825df7..b825340320 100644
--- a/app/user.go
+++ b/app/user.go
@@ -1685,11 +1685,10 @@ func (a *App) SearchUsersInChannel(channelId string, term string, options *model
 
 func (a *App) SearchUsersNotInChannel(teamId string, channelId string, term string, options *model.UserSearchOptions) ([]*model.User, *model.AppError) {
 	term = strings.TrimSpace(term)
-	result := <-a.Srv.Store.User().SearchNotInChannel(teamId, channelId, term, options)
-	if result.Err != nil {
-		return nil, result.Err
+	users, err := a.Srv.Store.User().SearchNotInChannel(teamId, channelId, term, options)
+	if err != nil {
+		return nil, err
 	}
-	users := result.Data.([]*model.User)
 
 	for _, user := range users {
 		a.SanitizeProfile(user, options.IsAdmin)
@@ -1851,7 +1850,12 @@ func (a *App) AutocompleteUsersInChannel(teamId string, channelId string, term s
 			close(uchan)
 		}()
 
-		nuchan := a.Srv.Store.User().SearchNotInChannel(teamId, channelId, term, options)
+		nuchan := make(chan store.StoreResult, 1)
+		go func() {
+			users, err := a.Srv.Store.User().SearchNotInChannel(teamId, channelId, term, options)
+			nuchan <- store.StoreResult{Data: users, Err: err}
+			close(nuchan)
+		}()
 
 		result := <-uchan
 		if result.Err != nil {
diff --git a/store/sqlstore/user_store.go b/store/sqlstore/user_store.go
index df044c3a47..51c1edd5a0 100644
--- a/store/sqlstore/user_store.go
+++ b/store/sqlstore/user_store.go
@@ -1273,24 +1273,26 @@ func (us SqlUserStore) SearchNotInTeam(notInTeamId string, term string, options
 	return result.Data.([]*model.User), nil
 }
 
-func (us SqlUserStore) SearchNotInChannel(teamId string, channelId string, term string, options *model.UserSearchOptions) store.StoreChannel {
-	return store.Do(func(result *store.StoreResult) {
-		query := us.usersQuery.
-			LeftJoin("ChannelMembers cm ON ( cm.UserId = u.Id AND cm.ChannelId = ? )", channelId).
-			Where("cm.UserId IS NULL").
-			OrderBy("Username ASC").
-			Limit(uint64(options.Limit))
+func (us SqlUserStore) SearchNotInChannel(teamId string, channelId string, term string, options *model.UserSearchOptions) ([]*model.User, *model.AppError) {
+	query := us.usersQuery.
+		LeftJoin("ChannelMembers cm ON ( cm.UserId = u.Id AND cm.ChannelId = ? )", channelId).
+		Where("cm.UserId IS NULL").
+		OrderBy("Username ASC").
+		Limit(uint64(options.Limit))
 
-		if teamId != "" {
-			query = query.Join("TeamMembers tm ON ( tm.UserId = u.Id AND tm.DeleteAt = 0 AND tm.TeamId = ? )", teamId)
-		}
+	if teamId != "" {
+		query = query.Join("TeamMembers tm ON ( tm.UserId = u.Id AND tm.DeleteAt = 0 AND tm.TeamId = ? )", teamId)
+	}
 
-		if options.GroupConstrained {
-			query = applyChannelGroupConstrainedFilter(query, channelId)
-		}
+	if options.GroupConstrained {
+		query = applyChannelGroupConstrainedFilter(query, channelId)
+	}
 
-		*result = us.performSearch(query, term, options)
-	})
+	result := us.performSearch(query, term, options)
+	if result.Err != nil {
+		return nil, result.Err
+	}
+	return result.Data.([]*model.User), nil
 }
 
 func (us SqlUserStore) SearchInChannel(channelId string, term string, options *model.UserSearchOptions) ([]*model.User, *model.AppError) {
diff --git a/store/store.go b/store/store.go
index c21ce251c4..5d97dbc852 100644
--- a/store/store.go
+++ b/store/store.go
@@ -291,7 +291,7 @@ type UserStore interface {
 	Search(teamId string, term string, options *model.UserSearchOptions) ([]*model.User, *model.AppError)
 	SearchNotInTeam(notInTeamId string, term string, options *model.UserSearchOptions) ([]*model.User, *model.AppError)
 	SearchInChannel(channelId string, term string, options *model.UserSearchOptions) ([]*model.User, *model.AppError)
-	SearchNotInChannel(teamId string, channelId string, term string, options *model.UserSearchOptions) StoreChannel
+	SearchNotInChannel(teamId string, channelId string, term string, options *model.UserSearchOptions) ([]*model.User, *model.AppError)
 	SearchWithoutTeam(term string, options *model.UserSearchOptions) ([]*model.User, *model.AppError)
 	AnalyticsGetInactiveUsersCount() (int64, *model.AppError)
 	AnalyticsGetSystemAdminCount() (int64, *model.AppError)
diff --git a/store/storetest/mocks/UserStore.go b/store/storetest/mocks/UserStore.go
index 26c5e93aa2..ba2cedc077 100644
--- a/store/storetest/mocks/UserStore.go
+++ b/store/storetest/mocks/UserStore.go
@@ -881,19 +881,28 @@ func (_m *UserStore) SearchInChannel(channelId string, term string, options *mod
 }
 
 // SearchNotInChannel provides a mock function with given fields: teamId, channelId, term, options
-func (_m *UserStore) SearchNotInChannel(teamId string, channelId string, term string, options *model.UserSearchOptions) store.StoreChannel {
+func (_m *UserStore) SearchNotInChannel(teamId string, channelId string, term string, options *model.UserSearchOptions) ([]*model.User, *model.AppError) {
 	ret := _m.Called(teamId, channelId, term, options)
 
-	var r0 store.StoreChannel
-	if rf, ok := ret.Get(0).(func(string, string, string, *model.UserSearchOptions) store.StoreChannel); ok {
+	var r0 []*model.User
+	if rf, ok := ret.Get(0).(func(string, string, string, *model.UserSearchOptions) []*model.User); ok {
 		r0 = rf(teamId, channelId, term, options)
 	} else {
 		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(store.StoreChannel)
+			r0 = ret.Get(0).([]*model.User)
 		}
 	}
 
-	return r0
+	var r1 *model.AppError
+	if rf, ok := ret.Get(1).(func(string, string, string, *model.UserSearchOptions) *model.AppError); ok {
+		r1 = rf(teamId, channelId, term, options)
+	} else {
+		if ret.Get(1) != nil {
+			r1 = ret.Get(1).(*model.AppError)
+		}
+	}
+
+	return r0, r1
 }
 
 // SearchNotInTeam provides a mock function with given fields: notInTeamId, term, options
diff --git a/store/storetest/user_store.go b/store/storetest/user_store.go
index 306934e6a9..77d7680295 100644
--- a/store/storetest/user_store.go
+++ b/store/storetest/user_store.go
@@ -2669,14 +2669,14 @@ func testUserStoreSearchNotInChannel(t *testing.T, ss store.Store) {
 
 	for _, testCase := range testCases {
 		t.Run(testCase.Description, func(t *testing.T) {
-			result := <-ss.User().SearchNotInChannel(
+			users, err := ss.User().SearchNotInChannel(
 				testCase.TeamId,
 				testCase.ChannelId,
 				testCase.Term,
 				testCase.Options,
 			)
-			require.Nil(t, result.Err)
-			assertUsers(t, testCase.Expected, result.Data.([]*model.User))
+			require.Nil(t, err)
+			assertUsers(t, testCase.Expected, users)
 		})
 	}
 }