diff --git a/src/Storages/MergeTree/MergeTreeData.cpp b/src/Storages/MergeTree/MergeTreeData.cpp
index a0d23b8ab22..b09f068f509 100644
--- a/src/Storages/MergeTree/MergeTreeData.cpp
+++ b/src/Storages/MergeTree/MergeTreeData.cpp
@@ -21,6 +21,7 @@
 #include <Interpreters/PartLog.h>
 #include <Interpreters/TreeRewriter.h>
 #include <Interpreters/Context.h>
+#include <Interpreters/inplaceBlockConversions.h>
 #include <Parsers/ASTFunction.h>
 #include <Parsers/ASTLiteral.h>
 #include <Parsers/ASTNameTypePair.h>
@@ -1482,6 +1483,7 @@ void MergeTreeData::checkAlterIsPossible(const AlterCommands & commands, const S
     for (const auto & column : old_metadata.getColumns().getAllPhysical())
         old_types.emplace(column.name, column.type.get());
 
+    NamesAndTypesList columns_to_check_conversion;
     for (const AlterCommand & command : commands)
     {
         /// Just validate partition expression
@@ -1571,9 +1573,9 @@ void MergeTreeData::checkAlterIsPossible(const AlterCommands & commands, const S
                 throw Exception("ALTER of key column " + backQuoteIfNeed(command.column_name) + " is forbidden",
                     ErrorCodes::ALTER_OF_COLUMN_IS_FORBIDDEN);
 
-            if (columns_alter_type_check_safe_for_partition.count(command.column_name))
+            if (command.type == AlterCommand::MODIFY_COLUMN)
             {
-                if (command.type == AlterCommand::MODIFY_COLUMN)
+                if (columns_alter_type_check_safe_for_partition.count(command.column_name))
                 {
                     auto it = old_types.find(command.column_name);
 
@@ -1584,11 +1586,8 @@ void MergeTreeData::checkAlterIsPossible(const AlterCommands & commands, const S
                                 + " is not safe because it can change the representation of partition key",
                             ErrorCodes::ALTER_OF_COLUMN_IS_FORBIDDEN);
                 }
-            }
 
-            if (columns_alter_type_metadata_only.count(command.column_name))
-            {
-                if (command.type == AlterCommand::MODIFY_COLUMN)
+                if (columns_alter_type_metadata_only.count(command.column_name))
                 {
                     auto it = old_types.find(command.column_name);
                     assert(it != old_types.end());
@@ -1598,6 +1597,12 @@ void MergeTreeData::checkAlterIsPossible(const AlterCommands & commands, const S
                                     + " is not safe because it can change the representation of primary key",
                             ErrorCodes::ALTER_OF_COLUMN_IS_FORBIDDEN);
                 }
+
+                if (old_metadata.getColumns().has(command.column_name))
+                {
+                    columns_to_check_conversion.push_back(
+                        new_metadata.getColumns().getPhysical(command.column_name));
+                }
             }
         }
     }
@@ -1605,6 +1610,12 @@ void MergeTreeData::checkAlterIsPossible(const AlterCommands & commands, const S
     checkProperties(new_metadata, old_metadata);
     checkTTLExpressions(new_metadata, old_metadata);
 
+    if (!columns_to_check_conversion.empty())
+    {
+        auto old_header = old_metadata.getSampleBlock();
+        performRequiredConversions(old_header, columns_to_check_conversion, global_context);
+    }
+
     if (old_metadata.hasSettingsChanges())
     {
         const auto current_changes = old_metadata.getSettingsChanges()->as<const ASTSetQuery &>().changes;
diff --git a/tests/queries/0_stateless/01732_alters_bad_conversions.reference b/tests/queries/0_stateless/01732_alters_bad_conversions.reference
new file mode 100644
index 00000000000..5f570c78579
--- /dev/null
+++ b/tests/queries/0_stateless/01732_alters_bad_conversions.reference
@@ -0,0 +1,4 @@
+CREATE TABLE default.bad_conversions\n(\n    `a` UInt32\n)\nENGINE = MergeTree\nORDER BY tuple()\nSETTINGS index_granularity = 8192
+0
+CREATE TABLE default.bad_conversions_2\n(\n    `e` Enum8(\'foo\' = 1, \'bar\' = 2)\n)\nENGINE = MergeTree\nORDER BY tuple()\nSETTINGS index_granularity = 8192
+0
diff --git a/tests/queries/0_stateless/01732_alters_bad_conversions.sql b/tests/queries/0_stateless/01732_alters_bad_conversions.sql
new file mode 100644
index 00000000000..27da5242368
--- /dev/null
+++ b/tests/queries/0_stateless/01732_alters_bad_conversions.sql
@@ -0,0 +1,17 @@
+DROP TABLE IF EXISTS bad_conversions;
+DROP TABLE IF EXISTS bad_conversions_2;
+
+CREATE TABLE bad_conversions (a UInt32) ENGINE = MergeTree ORDER BY tuple();
+INSERT INTO bad_conversions VALUES (1);
+ALTER TABLE bad_conversions MODIFY COLUMN a Array(String); -- { serverError 53 }
+SHOW CREATE TABLE bad_conversions;
+SELECT count() FROM system.mutations WHERE table = 'bad_conversions' AND database = currentDatabase();
+
+CREATE TABLE bad_conversions_2 (e Enum('foo' = 1, 'bar' = 2)) ENGINE = MergeTree ORDER BY tuple();
+INSERT INTO bad_conversions_2 VALUES (1);
+ALTER TABLE bad_conversions_2 MODIFY COLUMN e Enum('bar' = 1, 'foo' = 2); -- { serverError 70 }
+SHOW CREATE TABLE bad_conversions_2;
+SELECT count() FROM system.mutations WHERE table = 'bad_conversions_2' AND database = currentDatabase();
+
+DROP TABLE IF EXISTS bad_conversions;
+DROP TABLE IF EXISTS bad_conversions_2;