diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/database/queries/MangaQueries.kt b/app/src/main/java/eu/kanade/tachiyomi/data/database/queries/MangaQueries.kt
index fb3edf50e..16f17ed82 100755
--- a/app/src/main/java/eu/kanade/tachiyomi/data/database/queries/MangaQueries.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/database/queries/MangaQueries.kt
@@ -169,6 +169,26 @@ interface MangaQueries : DbProvider {
         )
         .prepare()
 
+    // SY -->
+    fun deleteMangasNotInLibraryAndNotRead() = db.delete()
+        .byQuery(
+            DeleteQuery.builder()
+                .table(MangaTable.TABLE)
+                .where(
+                    """
+                    ${MangaTable.COL_FAVORITE} = ? AND ${MangaTable.COL_ID} NOT IN (
+                        SELECT ${MergedTable.COL_MANGA_ID} FROM ${MergedTable.TABLE} WHERE ${MergedTable.COL_MANGA_ID} != ${MergedTable.COL_MERGE_ID}
+                    ) AND ${MangaTable.COL_ID} NOT IN (
+                        SELECT ${ChapterTable.COL_MANGA_ID} FROM ${ChapterTable.TABLE} WHERE ${ChapterTable.COL_READ} = 1 OR ${ChapterTable.COL_LAST_PAGE_READ} != 0
+                    )
+                    """.trimIndent()
+                )
+                .whereArgs(0)
+                .build()
+        )
+        .prepare()
+    // SY <--
+
     fun deleteMangas() = db.delete()
         .byQuery(
             DeleteQuery.builder()
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAdvancedController.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAdvancedController.kt
index 405325446..39b62ecf8 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAdvancedController.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAdvancedController.kt
@@ -12,6 +12,7 @@ import androidx.core.net.toUri
 import androidx.core.text.HtmlCompat
 import androidx.preference.PreferenceScreen
 import com.afollestad.materialdialogs.MaterialDialog
+import com.afollestad.materialdialogs.checkbox.checkBoxPrompt
 import com.afollestad.materialdialogs.list.listItemsMultiChoice
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.cache.ChapterCache
@@ -413,11 +414,20 @@ class SettingsAdvancedController : SettingsController() {
     }
 
     class ClearDatabaseDialogController : DialogController() {
+        // SY -->
+        var keepReadManga = false
+        // SY <--
+
         override fun onCreateDialog(savedViewState: Bundle?): Dialog {
             return MaterialDialog(activity!!)
                 .message(R.string.clear_database_confirmation)
+                // SY -->
+                .checkBoxPrompt(R.string.clear_db_exclude_read) {
+                    keepReadManga = it
+                }
+                // SY <--
                 .positiveButton(android.R.string.ok) {
-                    (targetController as? SettingsAdvancedController)?.clearDatabase()
+                    (targetController as? SettingsAdvancedController)?.clearDatabase(/* SY --> */keepReadManga/* SY <-- */)
                 }
                 .negativeButton(android.R.string.cancel)
         }
@@ -439,8 +449,14 @@ class SettingsAdvancedController : SettingsController() {
         activity?.toast(R.string.clear_history_completed)
     }
 
-    private fun clearDatabase() {
-        db.deleteMangasNotInLibrary().executeAsBlocking()
+    private fun clearDatabase(keepReadManga: Boolean) {
+        // SY -->
+        if (keepReadManga) {
+            db.deleteMangasNotInLibraryAndNotRead().executeAsBlocking()
+        } else {
+            db.deleteMangasNotInLibrary().executeAsBlocking()
+        }
+        // SY <--
         db.deleteHistoryNoLastRead().executeAsBlocking()
         activity?.toast(R.string.clear_database_completed)
     }
@@ -448,6 +464,8 @@ class SettingsAdvancedController : SettingsController() {
     private companion object {
         const val CLEAR_CACHE_KEY = "pref_clear_cache_key"
 
+        // SY -->
         private var job: Job? = null
+        // SY <--
     }
 }
diff --git a/app/src/main/res/values/strings_sy.xml b/app/src/main/res/values/strings_sy.xml
index fffa25b11..aea3dcb37 100644
--- a/app/src/main/res/values/strings_sy.xml
+++ b/app/src/main/res/values/strings_sy.xml
@@ -152,6 +152,7 @@
     <string name="data_saver_server">Bandwidth Hero Proxy Server</string>
     <string name="data_saver_server_summary">Put Bandwidth Hero Proxy server url here</string>
     <string name="update_monthly">Monthly</string>
+    <string name="clear_db_exclude_read">Keep manga with read chapters</string>
 
     <!-- Log Level -->
     <string name="log_minimal">Minimal</string>