diff --git a/ydb/core/kqp/ut/olap/sparsed_ut.cpp b/ydb/core/kqp/ut/olap/sparsed_ut.cpp
index 73b75f2cc53f..b9c9ad76206c 100644
--- a/ydb/core/kqp/ut/olap/sparsed_ut.cpp
+++ b/ydb/core/kqp/ut/olap/sparsed_ut.cpp
@@ -24,11 +24,16 @@ Y_UNIT_TEST_SUITE(KqpOlapSparsed) {
         const TVector<TString> FIELD_NAMES{"utf", "int", "uint", "float", "double"};
     public:
         TSparsedDataTest(const TString& storeName)
-            : Kikimr(Settings)
+            : Kikimr(GetKikimrSettings())
             , CSController(NKikimr::NYDBTest::TControllers::RegisterCSControllerGuard<NKikimr::NYDBTest::NColumnShard::TController>())
             , StoreName(storeName)
         {
+        }
 
+        TKikimrSettings GetKikimrSettings() {
+            NKikimrConfig::TFeatureFlags featureFlags;
+            featureFlags.SetEnableSparsedColumns(true);
+            return TKikimrSettings().SetWithSampleTables(false).SetFeatureFlags(featureFlags);
         }
 
         ui32 GetCount() const {
diff --git a/ydb/core/kqp/ut/olap/write_ut.cpp b/ydb/core/kqp/ut/olap/write_ut.cpp
index 8d9751f28193..ad9766fc2b9c 100644
--- a/ydb/core/kqp/ut/olap/write_ut.cpp
+++ b/ydb/core/kqp/ut/olap/write_ut.cpp
@@ -133,6 +133,9 @@ Y_UNIT_TEST_SUITE(KqpOlapWrite) {
 
     Y_UNIT_TEST(DefaultValues) {
         auto settings = TKikimrSettings().SetWithSampleTables(false);
+        NKikimrConfig::TFeatureFlags featureFlags;
+        featureFlags.SetEnableSparsedColumns(true);
+        settings.SetFeatureFlags(featureFlags);
         TKikimrRunner kikimr(settings);
         Tests::NCommon::TLoggerInit(kikimr).Initialize();
         TTypedLocalHelper helper("Utf8", kikimr);
diff --git a/ydb/core/protos/feature_flags.proto b/ydb/core/protos/feature_flags.proto
index aa7c2296efaf..6958f72925a7 100644
--- a/ydb/core/protos/feature_flags.proto
+++ b/ydb/core/protos/feature_flags.proto
@@ -158,4 +158,5 @@ message TFeatureFlags {
     optional bool EnablePgSyntax = 139 [default = true];
     optional bool EnableTieringInColumnShard = 140 [default = false];
     optional bool EnableMetadataObjectsOnServerless = 141 [default = true];
+    optional bool EnableSparsedColumns = 142 [default = false];
 }
diff --git a/ydb/core/tx/schemeshard/olap/operations/alter/standalone/update.cpp b/ydb/core/tx/schemeshard/olap/operations/alter/standalone/update.cpp
index cfb1367a224f..8404fb1f51ef 100644
--- a/ydb/core/tx/schemeshard/olap/operations/alter/standalone/update.cpp
+++ b/ydb/core/tx/schemeshard/olap/operations/alter/standalone/update.cpp
@@ -1,6 +1,7 @@
 #include "update.h"
 #include <ydb/core/tx/schemeshard/olap/operations/alter/abstract/converter.h>
 #include <ydb/core/tx/schemeshard/olap/common/common.h>
+#include <ydb/core/formats/arrow/accessor/common/const.h>
 
 namespace NKikimr::NSchemeShard::NOlap::NAlter {
 
@@ -51,6 +52,14 @@ NKikimr::TConclusionStatus TStandaloneSchemaUpdate::DoInitializeImpl(const TUpda
         }
     }
 
+    if (!AppData()->FeatureFlags.GetEnableSparsedColumns()) {
+        for (auto& [_, column]: targetSchema.GetColumns().GetColumns()) {
+            if (column.GetDefaultValue().GetValue() || (column.GetAccessorConstructor().GetClassName() == NKikimr::NArrow::NAccessor::TGlobalConst::SparsedDataAccessorName)) {
+                return TConclusionStatus::Fail("schema update error: sparsed columns are disabled");
+            }
+        }
+    }
+
     auto description = originalTable.GetTableInfoVerified().Description;
     targetSchema.Serialize(*description.MutableSchema());
     auto ttl = originalTable.GetTableTTLOptional() ? *originalTable.GetTableTTLOptional() : TOlapTTL();
diff --git a/ydb/core/tx/schemeshard/olap/operations/alter_store.cpp b/ydb/core/tx/schemeshard/olap/operations/alter_store.cpp
index ef9737cb07c3..98b69d62796f 100644
--- a/ydb/core/tx/schemeshard/olap/operations/alter_store.cpp
+++ b/ydb/core/tx/schemeshard/olap/operations/alter_store.cpp
@@ -1,6 +1,7 @@
 #include <ydb/core/tx/schemeshard/schemeshard__operation_part.h>
 #include <ydb/core/tx/schemeshard/schemeshard__operation_common.h>
 #include <ydb/core/tx/schemeshard/schemeshard_impl.h>
+#include <ydb/core/formats/arrow/accessor/common/const.h>
 
 #include "checks.h"
 
@@ -508,6 +509,17 @@ class TAlterOlapStore: public TSubOperation {
             return result;
         }
 
+        if (!AppData()->FeatureFlags.GetEnableSparsedColumns()) {
+            for (auto& [_, preset]: alterData->SchemaPresets) {
+                for (auto& [_, column]: preset.GetColumns().GetColumns()) {
+                    if (column.GetDefaultValue().GetValue() || (column.GetAccessorConstructor().GetClassName() == NKikimr::NArrow::NAccessor::TGlobalConst::SparsedDataAccessorName)) {
+                        result->SetError(NKikimrScheme::StatusSchemeError,"schema update error: sparsed columns are disabled");
+                        return result;
+                    }
+                }
+            }
+        }
+
         auto domainInfo = parentPath.DomainInfo();
         const TSchemeLimits& limits = domainInfo->GetSchemeLimits();
 
diff --git a/ydb/core/tx/schemeshard/ut_olap/ut_olap.cpp b/ydb/core/tx/schemeshard/ut_olap/ut_olap.cpp
index 90a14c747f8a..1a6a85e46e27 100644
--- a/ydb/core/tx/schemeshard/ut_olap/ut_olap.cpp
+++ b/ydb/core/tx/schemeshard/ut_olap/ut_olap.cpp
@@ -557,6 +557,17 @@ Y_UNIT_TEST_SUITE(TOlap) {
                 }
             }
         )", {NKikimrScheme::StatusAccepted});
+
+        env.TestWaitNotification(runtime, txId);
+        TestAlterOlapStore(runtime, ++txId, "/MyRoot", R"(
+            Name: "OlapStore"
+            AlterSchemaPresets {
+                Name: "default"
+                AlterSchema {
+                    AlterColumns { Name: "comment" DefaultValue: "10" }
+                }
+            }
+        )", {NKikimrScheme::StatusSchemeError});
     }
 
     Y_UNIT_TEST(AlterTtl) {
diff --git a/ydb/core/tx/schemeshard/ut_ttl/ut_ttl.cpp b/ydb/core/tx/schemeshard/ut_ttl/ut_ttl.cpp
index ce57f14992b3..1accb55c269b 100644
--- a/ydb/core/tx/schemeshard/ut_ttl/ut_ttl.cpp
+++ b/ydb/core/tx/schemeshard/ut_ttl/ut_ttl.cpp
@@ -1150,6 +1150,7 @@ Y_UNIT_TEST_SUITE(TSchemeShardColumnTableTTL) {
                 Columns { Name: "key" Type: "Uint64" NotNull: true }
                 Columns { Name: "modified_at" Type: "Timestamp" }
                 Columns { Name: "saved_at" Type: "Datetime" }
+                Columns { Name: "data" Type: "Utf8" }
                 KeyColumnNames: ["key"]
             }
         )");
@@ -1206,6 +1207,13 @@ Y_UNIT_TEST_SUITE(TSchemeShardColumnTableTTL) {
                 }
             }
         );
+        TestAlterColumnTable(runtime, ++txId, "/MyRoot", R"(
+            Name: "TTLEnabledTable"
+            AlterSchema {
+                AlterColumns {Name: "data" DefaultValue: "10"}
+            }
+        )", {NKikimrScheme::StatusSchemeError});
+        env.TestWaitNotification(runtime, txId);
     }
 
     Y_UNIT_TEST(AlterColumnTable_Negative) {