diff --git a/HMCLCore/src/main/java/org/jackhuang/hmcl/download/optifine/OptiFineBMCLVersionList.java b/HMCLCore/src/main/java/org/jackhuang/hmcl/download/optifine/OptiFineBMCLVersionList.java
index 2843a5ded..03cc73d6a 100644
--- a/HMCLCore/src/main/java/org/jackhuang/hmcl/download/optifine/OptiFineBMCLVersionList.java
+++ b/HMCLCore/src/main/java/org/jackhuang/hmcl/download/optifine/OptiFineBMCLVersionList.java
@@ -56,23 +56,29 @@ public final class OptiFineBMCLVersionList extends VersionList<OptiFineRemoteVer
 
             @Override
             public void execute() {
-                versions.clear();
-                Set<String> duplicates = new HashSet<>();
-                List<OptiFineVersion> root = JsonUtils.GSON.fromJson(task.getResult(), new TypeToken<List<OptiFineVersion>>() {
-                }.getType());
-                for (OptiFineVersion element : root) {
-                    String version = element.getType() + "_" + element.getPatch();
-                    String mirror = "http://bmclapi2.bangbang93.com/optifine/" + element.getGameVersion() + "/" + element.getType() + "/" + element.getPatch();
-                    if (!duplicates.add(mirror))
-                        continue;
+                lock.writeLock().lock();
 
-                    boolean isPre = element.getPatch() != null && (element.getPatch().startsWith("pre") || element.getPatch().startsWith("alpha"));
+                try {
+                    versions.clear();
+                    Set<String> duplicates = new HashSet<>();
+                    List<OptiFineVersion> root = JsonUtils.GSON.fromJson(task.getResult(), new TypeToken<List<OptiFineVersion>>() {
+                    }.getType());
+                    for (OptiFineVersion element : root) {
+                        String version = element.getType() + "_" + element.getPatch();
+                        String mirror = "http://bmclapi2.bangbang93.com/optifine/" + element.getGameVersion() + "/" + element.getType() + "/" + element.getPatch();
+                        if (!duplicates.add(mirror))
+                            continue;
 
-                    if (StringUtils.isBlank(element.getGameVersion()))
-                        continue;
+                        boolean isPre = element.getPatch() != null && (element.getPatch().startsWith("pre") || element.getPatch().startsWith("alpha"));
 
-                    String gameVersion = VersionNumber.normalize(element.getGameVersion());
-                    versions.put(gameVersion, new OptiFineRemoteVersion(gameVersion, version, mirror, isPre));
+                        if (StringUtils.isBlank(element.getGameVersion()))
+                            continue;
+
+                        String gameVersion = VersionNumber.normalize(element.getGameVersion());
+                        versions.put(gameVersion, new OptiFineRemoteVersion(gameVersion, version, mirror, isPre));
+                    }
+                } finally {
+                    lock.writeLock().unlock();
                 }
             }
         };