diff --git a/changelog.d/5918.bugfix b/changelog.d/5918.bugfix
new file mode 100644
index 0000000000..826e20aff6
--- /dev/null
+++ b/changelog.d/5918.bugfix
@@ -0,0 +1 @@
+If media cache is large, Settings > General takes a long time to open
diff --git a/vector/src/main/java/im/vector/app/core/utils/FileUtils.kt b/vector/src/main/java/im/vector/app/core/utils/FileUtils.kt
index c735b8b33d..63f141ef52 100644
--- a/vector/src/main/java/im/vector/app/core/utils/FileUtils.kt
+++ b/vector/src/main/java/im/vector/app/core/utils/FileUtils.kt
@@ -17,6 +17,7 @@
 package im.vector.app.core.utils
 
 import android.content.Context
+import androidx.annotation.WorkerThread
 import timber.log.Timber
 import java.io.File
 import java.util.Locale
@@ -125,6 +126,7 @@ fun getFileExtension(fileUri: String): String? {
  * Size
  * ========================================================================================== */
 
+@WorkerThread
 fun getSizeOfFiles(root: File): Long {
     return root.walkTopDown()
             .onEnter {
diff --git a/vector/src/main/java/im/vector/app/features/settings/VectorSettingsGeneralFragment.kt b/vector/src/main/java/im/vector/app/features/settings/VectorSettingsGeneralFragment.kt
index 548a7be180..c90f55d22a 100644
--- a/vector/src/main/java/im/vector/app/features/settings/VectorSettingsGeneralFragment.kt
+++ b/vector/src/main/java/im/vector/app/features/settings/VectorSettingsGeneralFragment.kt
@@ -250,37 +250,28 @@ class VectorSettingsGeneralFragment :
 
         // clear medias cache
         findPreference<VectorPreference>(VectorPreferences.SETTINGS_CLEAR_MEDIA_CACHE_PREFERENCE_KEY)!!.let {
-            val size = getSizeOfFiles(File(requireContext().cacheDir, DiskCache.Factory.DEFAULT_DISK_CACHE_DIR)) + session.fileService().getCacheSize()
-
-            it.summary = TextUtils.formatFileSize(requireContext(), size.toLong())
-
-            it.onPreferenceClickListener = Preference.OnPreferenceClickListener {
-                lifecycleScope.launch(Dispatchers.Main) {
-                    // On UI Thread
-                    displayLoadingView()
-
-                    Glide.get(requireContext()).clearMemory()
-                    session.fileService().clearCache()
-
-                    var newSize: Long
-
-                    withContext(Dispatchers.IO) {
-                        // On BG thread
-                        Glide.get(requireContext()).clearDiskCache()
-
-                        newSize = getSizeOfFiles(File(requireContext().cacheDir, DiskCache.Factory.DEFAULT_DISK_CACHE_DIR))
-                        newSize += session.fileService().getCacheSize()
+            lifecycleScope.launch(Dispatchers.Main) {
+                it.summary = getString(R.string.loading)
+                val size = getCacheSize()
+                it.summary = TextUtils.formatFileSize(requireContext(), size)
+                it.onPreferenceClickListener = Preference.OnPreferenceClickListener {
+                    lifecycleScope.launch(Dispatchers.Main) {
+                        // On UI Thread
+                        displayLoadingView()
+                        Glide.get(requireContext()).clearMemory()
+                        session.fileService().clearCache()
+                        val newSize = withContext(Dispatchers.IO) {
+                            // On BG thread
+                            Glide.get(requireContext()).clearDiskCache()
+                            getCacheSize()
+                        }
+                        it.summary = TextUtils.formatFileSize(requireContext(), newSize)
+                        hideLoadingView()
                     }
-
-                    it.summary = TextUtils.formatFileSize(requireContext(), newSize)
-
-                    hideLoadingView()
+                    false
                 }
-
-                false
             }
         }
-
         // Sign out
         findPreference<VectorPreference>("SETTINGS_SIGN_OUT_KEY")!!
                 .onPreferenceClickListener = Preference.OnPreferenceClickListener {
@@ -292,6 +283,11 @@ class VectorSettingsGeneralFragment :
         }
     }
 
+    private suspend fun getCacheSize(): Long = withContext(Dispatchers.IO) {
+        getSizeOfFiles(File(requireContext().cacheDir, DiskCache.Factory.DEFAULT_DISK_CACHE_DIR)) +
+                session.fileService().getCacheSize()
+    }
+
     override fun onResume() {
         super.onResume()
         // Refresh identity server summary