diff --git a/src/Orchard/Data/Migration/AutomaticDataMigrations.cs b/src/Orchard/Data/Migration/AutomaticDataMigrations.cs
index f62e4d4b2..ebbe0763c 100644
--- a/src/Orchard/Data/Migration/AutomaticDataMigrations.cs
+++ b/src/Orchard/Data/Migration/AutomaticDataMigrations.cs
@@ -89,7 +89,7 @@ namespace Orchard.Data.Migration {
         private void EnsureDistributedLockSchemaExists() {
             // Ensure the distributed lock record schema exists.
             var schemaBuilder = new SchemaBuilder(_dataMigrationInterpreter);
-            var distributedLockSchemaBuilder = new DistributedLockSchemaBuilder(schemaBuilder);
+            var distributedLockSchemaBuilder = new DistributedLockSchemaBuilder(schemaBuilder, _shellSettings);
             if (!distributedLockSchemaBuilder.SchemaExists()) {
 
                 // Workaround to avoid some Transaction issue for PostgreSQL.
diff --git a/src/Orchard/Tasks/Locking/Services/DistributedLockSchemaBuilder.cs b/src/Orchard/Tasks/Locking/Services/DistributedLockSchemaBuilder.cs
index 367c004ef..104c5e320 100644
--- a/src/Orchard/Tasks/Locking/Services/DistributedLockSchemaBuilder.cs
+++ b/src/Orchard/Tasks/Locking/Services/DistributedLockSchemaBuilder.cs
@@ -1,24 +1,37 @@
 using System;
 using Orchard.Data.Migration.Schema;
+using Orchard.Environment.Configuration;
 
 namespace Orchard.Tasks.Locking.Services {
     public class DistributedLockSchemaBuilder {
         private readonly SchemaBuilder _schemaBuilder;
+        private readonly ShellSettings _shellSettings;
         private const string TableName = "Orchard_Framework_DistributedLockRecord";
 
-        public DistributedLockSchemaBuilder(SchemaBuilder schemaBuilder) {
+        public DistributedLockSchemaBuilder(SchemaBuilder schemaBuilder, ShellSettings shellSettings) {
             _schemaBuilder = schemaBuilder;
+            _shellSettings = shellSettings;
         }
 
         public void CreateSchema() {
             _schemaBuilder.CreateTable(TableName, table => table
                 .Column<int>("Id", column => column.PrimaryKey().Identity())
-                .Column<string>("Name", column => column.NotNull().WithLength(512).Unique())
+                // Keep 512 chars but avoid inline .Unique() to prevent MySQL TEXT/BLOB key-length errors.
+                .Column<string>("Name", column => column.NotNull().WithLength(512))
                 .Column<string>("MachineName", column => column.WithLength(256))
                 .Column<DateTime>("CreatedUtc")
                 .Column<DateTime>("ValidUntilUtc", column => column.Nullable()));
 
+            // MySQL-specific adjustment to avoid error when adding the unique constraint.
+            if (string.Equals(_shellSettings.DataProvider, "MySql", StringComparison.OrdinalIgnoreCase)) {
+                // Force VARCHAR(512) on MySQL (some interpreters map >255 to TEXT).
+                _schemaBuilder.ExecuteSql(
+                    $"ALTER TABLE {_schemaBuilder.TableDbName(TableName)} MODIFY COLUMN Name VARCHAR(512) NOT NULL;",
+                    cmd => cmd.ForProvider("MySql"));
+            }
+
             _schemaBuilder.AlterTable(TableName, table => {
+                table.AddUniqueConstraint("UQ_DistributedLockRecord_Name", "Name");
                 table.CreateIndex("IDX_DistributedLockRecord_Name", "Name");
             });
         }