diff --git a/eden/fs/inodes/FileInode.cpp b/eden/fs/inodes/FileInode.cpp
index 1f218549f05fd..771a53aeefe5c 100644
--- a/eden/fs/inodes/FileInode.cpp
+++ b/eden/fs/inodes/FileInode.cpp
@@ -986,7 +986,7 @@ ImmediateFuture<struct stat> FileInode::stat(
   }
 }
 
-void FileInode::updateBlockCount(FOLLY_MAYBE_UNUSED struct stat& st) {
+void FileInode::updateBlockCount([[maybe_unused]] struct stat& st) {
   // win32 does not have stat::st_blocks
 #ifndef _WIN32
   // Compute a value to store in st_blocks based on st_size.
diff --git a/eden/fs/inodes/InodeBase.cpp b/eden/fs/inodes/InodeBase.cpp
index 6689eea946ee5..09bb13425cc75 100644
--- a/eden/fs/inodes/InodeBase.cpp
+++ b/eden/fs/inodes/InodeBase.cpp
@@ -42,7 +42,7 @@ InodeBase::InodeBase(EdenMount* mount)
 InodeBase::InodeBase(
     InodeNumber ino,
     mode_t initialMode,
-    FOLLY_MAYBE_UNUSED const std::optional<InodeTimestamps>& initialTimestamps,
+    [[maybe_unused]] const std::optional<InodeTimestamps>& initialTimestamps,
     TreeInodePtr parent,
     PathComponentPiece name)
     : ino_{ino},
@@ -347,7 +347,7 @@ void InodeBase::updateAtime() {
 #endif
 }
 
-void InodeBase::updateMtimeAndCtime(FOLLY_MAYBE_UNUSED EdenTimestamp now) {
+void InodeBase::updateMtimeAndCtime([[maybe_unused]] EdenTimestamp now) {
 #ifndef _WIN32
   XLOG(DBG9) << "Updating timestamps for : " << ino_;
   getMount()->getInodeMetadataTable()->modifyOrThrow(
diff --git a/eden/fs/inodes/InodeCatalog.h b/eden/fs/inodes/InodeCatalog.h
index c1a9e731d78de..3e9553317fff1 100644
--- a/eden/fs/inodes/InodeCatalog.h
+++ b/eden/fs/inodes/InodeCatalog.h
@@ -170,10 +170,10 @@ class InodeCatalog {
    * directory when EdenFS is not running.
    */
   virtual InodeNumber scanLocalChanges(
-      FOLLY_MAYBE_UNUSED std::shared_ptr<const EdenConfig> config,
-      FOLLY_MAYBE_UNUSED AbsolutePathPiece mountPath,
-      FOLLY_MAYBE_UNUSED bool windowsSymlinksEnabled,
-      FOLLY_MAYBE_UNUSED LookupCallback& callback) {
+      [[maybe_unused]] std::shared_ptr<const EdenConfig> config,
+      [[maybe_unused]] AbsolutePathPiece mountPath,
+      [[maybe_unused]] bool windowsSymlinksEnabled,
+      [[maybe_unused]] LookupCallback& callback) {
     EDEN_BUG() << "UNIMPLEMENTED";
   }
 
diff --git a/eden/fs/inodes/InodeMap.cpp b/eden/fs/inodes/InodeMap.cpp
index e264836aca3a4..73855f054def4 100644
--- a/eden/fs/inodes/InodeMap.cpp
+++ b/eden/fs/inodes/InodeMap.cpp
@@ -828,7 +828,7 @@ void InodeMap::setUnmounted() {
 }
 
 Future<SerializedInodeMap> InodeMap::shutdown(
-    FOLLY_MAYBE_UNUSED bool doTakeover) {
+    [[maybe_unused]] bool doTakeover) {
   // Record that we are in the process of shutting down.
   auto future = Future<folly::Unit>::makeEmpty();
   {
diff --git a/eden/fs/inodes/Overlay.cpp b/eden/fs/inodes/Overlay.cpp
index 0084e41d70e90..eb8295d84770e 100644
--- a/eden/fs/inodes/Overlay.cpp
+++ b/eden/fs/inodes/Overlay.cpp
@@ -313,8 +313,8 @@ folly::SemiFuture<Unit> Overlay::initialize(
 void Overlay::initOverlay(
     std::shared_ptr<const EdenConfig> config,
     std::optional<AbsolutePath> mountPath,
-    FOLLY_MAYBE_UNUSED const OverlayChecker::ProgressCallback& progressCallback,
-    FOLLY_MAYBE_UNUSED InodeCatalog::LookupCallback& lookupCallback) {
+    [[maybe_unused]] const OverlayChecker::ProgressCallback& progressCallback,
+    [[maybe_unused]] InodeCatalog::LookupCallback& lookupCallback) {
   IORequest req{this};
   auto optNextInodeNumber =
       inodeCatalog_->initOverlay(/*createIfNonExisting=*/true);
diff --git a/eden/fs/inodes/TreeInode.cpp b/eden/fs/inodes/TreeInode.cpp
index 33824309fb51e..7fb35424dad2c 100644
--- a/eden/fs/inodes/TreeInode.cpp
+++ b/eden/fs/inodes/TreeInode.cpp
@@ -1104,7 +1104,7 @@ FileInodePtr TreeInode::createImpl(
     folly::Synchronized<TreeInodeState>::LockedPtr contents,
     PathComponentPiece name,
     mode_t mode,
-    FOLLY_MAYBE_UNUSED ByteRange fileContents,
+    [[maybe_unused]] ByteRange fileContents,
     InvalidationRequired invalidate,
     std::chrono::system_clock::time_point startTime) {
 #ifndef _WIN32
@@ -3835,7 +3835,7 @@ bool needDecFsRefcount(InodeMap& inodeMap, InodeNumber ino) {
 folly::Try<folly::Unit> TreeInode::invalidateChannelEntryCache(
     TreeInodeState&,
     PathComponentPiece name,
-    FOLLY_MAYBE_UNUSED std::optional<InodeNumber> ino) {
+    [[maybe_unused]] std::optional<InodeNumber> ino) {
   auto faultTry = getMount()->getServerState()->getFaultInjector().checkTry(
       "invalidateChannelEntryCache", name);
   if (faultTry.hasException()) {
diff --git a/eden/fs/inodes/lmdbcatalog/LMDBInodeCatalog.cpp b/eden/fs/inodes/lmdbcatalog/LMDBInodeCatalog.cpp
index 5fd4a734f9649..d40f14de6d77c 100644
--- a/eden/fs/inodes/lmdbcatalog/LMDBInodeCatalog.cpp
+++ b/eden/fs/inodes/lmdbcatalog/LMDBInodeCatalog.cpp
@@ -87,7 +87,7 @@ InodeNumber LMDBInodeCatalog::scanLocalChanges(
     std::shared_ptr<const EdenConfig> /*config*/,
     AbsolutePathPiece /*mountPath*/,
     bool /*windowsSymlinksEnabled*/,
-    FOLLY_MAYBE_UNUSED InodeCatalog::LookupCallback& /*callback*/) {
+    [[maybe_unused]] InodeCatalog::LookupCallback& /*callback*/) {
   NOT_IMPLEMENTED();
 }
 } // namespace facebook::eden
diff --git a/eden/fs/inodes/memcatalog/MemInodeCatalog.cpp b/eden/fs/inodes/memcatalog/MemInodeCatalog.cpp
index b9be943c4e557..4759a6c255604 100644
--- a/eden/fs/inodes/memcatalog/MemInodeCatalog.cpp
+++ b/eden/fs/inodes/memcatalog/MemInodeCatalog.cpp
@@ -181,15 +181,15 @@ InodeNumber MemInodeCatalog::nextInodeNumber() {
 }
 
 std::optional<fsck::InodeInfo> MemInodeCatalog::loadInodeInfo(
-    FOLLY_MAYBE_UNUSED InodeNumber number) {
+    [[maybe_unused]] InodeNumber number) {
   return std::nullopt;
 }
 
 InodeNumber MemInodeCatalog::scanLocalChanges(
-    FOLLY_MAYBE_UNUSED std::shared_ptr<const EdenConfig> config,
-    FOLLY_MAYBE_UNUSED AbsolutePathPiece mountPath,
-    FOLLY_MAYBE_UNUSED bool windowsSymlinksEnabled,
-    FOLLY_MAYBE_UNUSED InodeCatalog::LookupCallback& callback) {
+    [[maybe_unused]] std::shared_ptr<const EdenConfig> config,
+    [[maybe_unused]] AbsolutePathPiece mountPath,
+    [[maybe_unused]] bool windowsSymlinksEnabled,
+    [[maybe_unused]] InodeCatalog::LookupCallback& callback) {
 #ifdef _WIN32
   windowsFsckScanLocalChanges(
       config,
diff --git a/eden/fs/inodes/sqlitecatalog/SqliteInodeCatalog.cpp b/eden/fs/inodes/sqlitecatalog/SqliteInodeCatalog.cpp
index f69afb392155f..f73da7cab4e76 100644
--- a/eden/fs/inodes/sqlitecatalog/SqliteInodeCatalog.cpp
+++ b/eden/fs/inodes/sqlitecatalog/SqliteInodeCatalog.cpp
@@ -119,8 +119,8 @@ std::vector<InodeNumber> SqliteInodeCatalog::getAllParentInodeNumbers() {
 InodeNumber SqliteInodeCatalog::scanLocalChanges(
     std::shared_ptr<const EdenConfig> config,
     AbsolutePathPiece mountPath,
-    FOLLY_MAYBE_UNUSED bool windowsSymlinksEnabled,
-    FOLLY_MAYBE_UNUSED InodeCatalog::LookupCallback& callback) {
+    [[maybe_unused]] bool windowsSymlinksEnabled,
+    [[maybe_unused]] InodeCatalog::LookupCallback& callback) {
 #ifdef _WIN32
   windowsFsckScanLocalChanges(
       config,
diff --git a/eden/fs/inodes/test/CheckoutTest.cpp b/eden/fs/inodes/test/CheckoutTest.cpp
index 822d68e390cce..c41c7a703a2e0 100644
--- a/eden/fs/inodes/test/CheckoutTest.cpp
+++ b/eden/fs/inodes/test/CheckoutTest.cpp
@@ -74,7 +74,7 @@ inline void PrintTo(
 
 namespace {
 
-bool isExecutable(FOLLY_MAYBE_UNUSED int perms) {
+bool isExecutable([[maybe_unused]] int perms) {
 #ifndef _WIN32
   return perms & S_IXUSR;
 #else
@@ -156,7 +156,7 @@ void loadInodes(
     RelativePathPiece path,
     LoadBehavior loadType,
     std::optional<folly::StringPiece> expectedContents,
-    FOLLY_MAYBE_UNUSED mode_t expectedPerms) {
+    [[maybe_unused]] mode_t expectedPerms) {
   switch (loadType) {
     case LoadBehavior::NONE:
       return;
@@ -390,7 +390,7 @@ void testModifyFile(
   }
 
   testMount.getClock().advance(10min);
-  FOLLY_MAYBE_UNUSED auto checkoutStart = testMount.getClock().getTimePoint();
+  [[maybe_unused]] auto checkoutStart = testMount.getClock().getTimePoint();
   auto executor = testMount.getServerExecutor().get();
   auto checkoutResult = testMount.getEdenMount()
                             ->checkout(
diff --git a/eden/fs/service/EdenServer.cpp b/eden/fs/service/EdenServer.cpp
index 112f8bc0d5b5e..ea6288cd298ef 100644
--- a/eden/fs/service/EdenServer.cpp
+++ b/eden/fs/service/EdenServer.cpp
@@ -1509,8 +1509,8 @@ void EdenServer::unregisterInodePopulationReportsCallback() {
 }
 
 Future<Unit> EdenServer::performTakeoverStart(
-    FOLLY_MAYBE_UNUSED std::shared_ptr<EdenMount> edenMount,
-    FOLLY_MAYBE_UNUSED TakeoverData::MountInfo&& info) {
+    [[maybe_unused]] std::shared_ptr<EdenMount> edenMount,
+    [[maybe_unused]] TakeoverData::MountInfo&& info) {
 #ifndef _WIN32
   auto mountPath = info.mountPath;
 
@@ -1531,8 +1531,8 @@ Future<Unit> EdenServer::performTakeoverStart(
 }
 
 Future<Unit> EdenServer::completeTakeoverStart(
-    FOLLY_MAYBE_UNUSED std::shared_ptr<EdenMount> edenMount,
-    FOLLY_MAYBE_UNUSED TakeoverData::MountInfo&& info) {
+    [[maybe_unused]] std::shared_ptr<EdenMount> edenMount,
+    [[maybe_unused]] TakeoverData::MountInfo&& info) {
   if (auto channelData = std::get_if<FuseChannelData>(&info.channelInfo)) {
     // Start up the fuse workers.
     return folly::makeFutureWith(
diff --git a/eden/fs/service/EdenServiceHandler.cpp b/eden/fs/service/EdenServiceHandler.cpp
index c41a698abc39c..2095d89cbef10 100644
--- a/eden/fs/service/EdenServiceHandler.cpp
+++ b/eden/fs/service/EdenServiceHandler.cpp
@@ -3161,9 +3161,9 @@ folly::SemiFuture<folly::Unit> EdenServiceHandler::semifuture_prefetchFiles(
 }
 
 folly::SemiFuture<struct folly::Unit> EdenServiceHandler::semifuture_chown(
-    FOLLY_MAYBE_UNUSED std::unique_ptr<std::string> mountPoint,
-    FOLLY_MAYBE_UNUSED int32_t uid,
-    FOLLY_MAYBE_UNUSED int32_t gid) {
+    [[maybe_unused]] std::unique_ptr<std::string> mountPoint,
+    [[maybe_unused]] int32_t uid,
+    [[maybe_unused]] int32_t gid) {
 #ifndef _WIN32
   auto handle = lookupMount(mountPoint);
   return handle.getEdenMount().chown(uid, gid).ensure([handle] {}).semi();
@@ -3765,8 +3765,8 @@ void EdenServiceHandler::debugInodeStatus(
 }
 
 void EdenServiceHandler::debugOutstandingFuseCalls(
-    FOLLY_MAYBE_UNUSED std::vector<FuseCall>& outstandingCalls,
-    FOLLY_MAYBE_UNUSED std::unique_ptr<std::string> mountPoint) {
+    [[maybe_unused]] std::vector<FuseCall>& outstandingCalls,
+    [[maybe_unused]] std::unique_ptr<std::string> mountPoint) {
 #ifndef _WIN32
   auto helper = INSTRUMENT_THRIFT_CALL(DBG2);
 
@@ -3802,8 +3802,8 @@ void EdenServiceHandler::debugOutstandingNfsCalls(
 }
 
 void EdenServiceHandler::debugOutstandingPrjfsCalls(
-    FOLLY_MAYBE_UNUSED std::vector<PrjfsCall>& outstandingCalls,
-    FOLLY_MAYBE_UNUSED std::unique_ptr<std::string> mountPoint) {
+    [[maybe_unused]] std::vector<PrjfsCall>& outstandingCalls,
+    [[maybe_unused]] std::unique_ptr<std::string> mountPoint) {
 #ifdef _WIN32
   auto helper = INSTRUMENT_THRIFT_CALL(DBG2);
 
@@ -4026,9 +4026,9 @@ int64_t EdenServiceHandler::debugDropAllPendingRequests() {
 }
 
 int64_t EdenServiceHandler::unloadInodeForPath(
-    FOLLY_MAYBE_UNUSED unique_ptr<string> mountPoint,
-    FOLLY_MAYBE_UNUSED std::unique_ptr<std::string> path,
-    FOLLY_MAYBE_UNUSED std::unique_ptr<TimeSpec> age) {
+    [[maybe_unused]] unique_ptr<string> mountPoint,
+    [[maybe_unused]] std::unique_ptr<std::string> path,
+    [[maybe_unused]] std::unique_ptr<TimeSpec> age) {
 #ifndef _WIN32
   auto helper = INSTRUMENT_THRIFT_CALL(DBG1, *mountPoint, *path);
   auto mountHandle = lookupMount(mountPoint);
@@ -4237,8 +4237,8 @@ void EdenServiceHandler::flushStatsNow() {
 
 folly::SemiFuture<Unit>
 EdenServiceHandler::semifuture_invalidateKernelInodeCache(
-    FOLLY_MAYBE_UNUSED std::unique_ptr<std::string> mountPoint,
-    FOLLY_MAYBE_UNUSED std::unique_ptr<std::string> path) {
+    [[maybe_unused]] std::unique_ptr<std::string> mountPoint,
+    [[maybe_unused]] std::unique_ptr<std::string> path) {
   auto helper = INSTRUMENT_THRIFT_CALL(DBG2, *mountPoint, *path);
   auto mountHandle = lookupMount(mountPoint);
 #ifndef _WIN32
diff --git a/eden/fs/service/StartupLogger.cpp b/eden/fs/service/StartupLogger.cpp
index 47235ee86461c..9968bc9b19f1b 100644
--- a/eden/fs/service/StartupLogger.cpp
+++ b/eden/fs/service/StartupLogger.cpp
@@ -204,7 +204,7 @@ DaemonStartupLogger::ChildHandler::~ChildHandler() {
 
 DaemonStartupLogger::ChildHandler DaemonStartupLogger::spawnImpl(
     StringPiece logPath,
-    FOLLY_MAYBE_UNUSED PrivHelper* privHelper,
+    [[maybe_unused]] PrivHelper* privHelper,
     const std::vector<std::string>& argv) {
   XDCHECK(!logPath.empty());
 
diff --git a/eden/fs/service/ThriftGetObjectImpl.h b/eden/fs/service/ThriftGetObjectImpl.h
index 9f437b1c5e4c9..b01eac4ed7804 100644
--- a/eden/fs/service/ThriftGetObjectImpl.h
+++ b/eden/fs/service/ThriftGetObjectImpl.h
@@ -103,7 +103,7 @@ folly::Try<BlobMetadata> transformToTryMetadata(
       edenMount->getObjectStore()->renderObjectId(id))};
 }
 
-// FOLLY_MAYBE_UNUSED: This specialization is used and nessecary, but clang's
+// [[maybe_unused]]: This specialization is used and nessecary, but clang's
 // maybe unused thing thinks that the templated transformToTryMetadata above
 // will over shadow this specialization. So clang will think this is unused.
 // Apparently, clang does not bother trying to instantate a templated thing.
@@ -112,7 +112,7 @@ folly::Try<BlobMetadata> transformToTryMetadata(
 // https://stackoverflow.com/questions/66986718/c-clang-emit-warning-about-unused-template-variable)
 // Maybe concepts in C++20 will clear this up, but we aren't there yet.
 template <>
-FOLLY_MAYBE_UNUSED folly::Try<BlobMetadata> transformToTryMetadata(
+[[maybe_unused]] folly::Try<BlobMetadata> transformToTryMetadata(
     folly::Try<std::optional<BlobMetadata>> metadata,
     std::shared_ptr<EdenMount> edenMount,
     ObjectId id);
diff --git a/eden/fs/testharness/TestMount.cpp b/eden/fs/testharness/TestMount.cpp
index 3cb82536e0637..3d2cc07d10363 100644
--- a/eden/fs/testharness/TestMount.cpp
+++ b/eden/fs/testharness/TestMount.cpp
@@ -493,7 +493,7 @@ bool TestMount::hasOverlayDir(InodeNumber ino) const {
   return edenMount_->getOverlay()->hasOverlayDir(ino);
 }
 
-bool TestMount::hasMetadata(FOLLY_MAYBE_UNUSED InodeNumber ino) const {
+bool TestMount::hasMetadata([[maybe_unused]] InodeNumber ino) const {
 #ifndef _WIN32
   return edenMount_->getInodeMetadataTable()->getOptional(ino).has_value();
 #else
diff --git a/eden/fs/utils/ProcUtil.cpp b/eden/fs/utils/ProcUtil.cpp
index fcdf8b26ac481..2c7617fb0d64c 100644
--- a/eden/fs/utils/ProcUtil.cpp
+++ b/eden/fs/utils/ProcUtil.cpp
@@ -237,7 +237,7 @@ std::optional<size_t> calculatePrivateBytes() {
 #endif
 }
 
-ProcessList readProcessIdsForPath(FOLLY_MAYBE_UNUSED const AbsolutePath& path) {
+ProcessList readProcessIdsForPath([[maybe_unused]] const AbsolutePath& path) {
   ProcessList pids;
 #ifdef __APPLE__
   // Obtain the number of bytes to allocate for the pids buffer.