diff --git a/eos/db/saveddata/databaseRepair.py b/eos/db/saveddata/databaseRepair.py
new file mode 100644
index 000000000..ede0f2fde
--- /dev/null
+++ b/eos/db/saveddata/databaseRepair.py
@@ -0,0 +1,104 @@
+# ===============================================================================
+# Copyright (C) 2010 Diego Duclos
+#
+# This file is part of pyfa.
+#
+# pyfa is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# pyfa is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with pyfa.  If not, see <http://www.gnu.org/licenses/>.
+# ===============================================================================
+
+import sqlalchemy
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class DatabaseCleanup:
+    def __init__(self):
+        pass
+
+    @staticmethod
+    def OrphanedCharacterSkills(saveddata_engine):
+        # Finds and fixes database corruption issues.
+        logger.debug("Start databsae validation and cleanup.")
+
+        # Find orphaned character skills.
+        # This solves an issue where the character doesn't exist, but skills for that character do.
+        # See issue #917
+        try:
+            logger.debug("Running database cleanup for character skills.")
+            results = saveddata_engine.execute("SELECT COUNT(*) AS num FROM characterSkills "
+                                               "WHERE characterID NOT IN (SELECT ID from characters)")
+            row = results.first()
+
+            if row and row['num']:
+                delete = saveddata_engine.execute("DELETE FROM characterSkills WHERE characterID NOT IN (SELECT ID from characters)")
+                logger.error("Database corruption found. Cleaning up %d records.", delete.rowcount)
+
+        except sqlalchemy.exc.DatabaseError:
+            logger.error("Failed to connect to database.")
+
+    @staticmethod
+    def OrphanedFitDamagePatterns(saveddata_engine):
+        # Find orphaned damage patterns.
+        # This solves an issue where the damage pattern doesn't exist, but fits reference the pattern.
+        # See issue #777
+        try:
+            logger.debug("Running database cleanup for orphaned damage patterns attached to fits.")
+
+            results = saveddata_engine.execute("SELECT COUNT(*) AS num FROM fits WHERE damagePatternID NOT IN (SELECT ID FROM damagePatterns) OR damagePatternID IS NULL")
+            row = results.first()
+
+            if row and row['num']:
+                # Get Uniform damage pattern ID
+                query = saveddata_engine.execute("SELECT ID FROM damagePatterns WHERE name = 'Uniform'")
+                rows = query.fetchall()
+
+                if len(rows) == 0:
+                    logger.error("Missing uniform damage pattern.")
+                elif len(rows) > 1:
+                    logger.error("More than one uniform damage pattern found.")
+                else:
+                    uniform_damage_pattern_id = rows[0]['ID']
+                    update = saveddata_engine.execute("UPDATE 'fits' SET 'damagePatternID' = ? "
+                                                      "WHERE damagePatternID NOT IN (SELECT ID FROM damagePatterns) OR damagePatternID IS NULL",
+                                                       uniform_damage_pattern_id)
+                    logger.error("Database corruption found. Cleaning up %d records.", update.rowcount)
+        except sqlalchemy.exc.DatabaseError:
+            logger.error("Failed to connect to database.")
+
+    @staticmethod
+    def OrphanedFitCharacterIDs(saveddata_engine):
+        # Find orphaned character IDs. This solves an issue where the character doesn't exist, but fits reference the pattern.
+        try:
+            logger.debug("Running database cleanup for orphaned characters attached to fits.")
+            results = saveddata_engine.execute("SELECT COUNT(*) AS num FROM fits WHERE characterID NOT IN (SELECT ID FROM characters) OR characterID IS NULL")
+            row = results.first()
+
+            if row['num']:
+                # Get All 5 character ID
+                query = saveddata_engine.execute("SELECT ID FROM characters WHERE name = 'All 5'")
+                rows = query.fetchall()
+
+                if len(rows) == 0:
+                    logger.error("Missing 'All 5' character.")
+                elif len(rows) > 1:
+                    logger.error("More than one 'All 5' character found.")
+                else:
+                    all5_id = rows[0]['ID']
+                    update = saveddata_engine.execute("UPDATE 'fits' SET 'characterID' = ? "
+                                                      "WHERE characterID not in (select ID from characters) OR characterID IS NULL",
+                                                       all5_id)
+                    logger.error("Database corruption found. Cleaning up %d records.", update.rowcount)
+        except sqlalchemy.exc.DatabaseError:
+            logger.error("Failed to connect to database.")
diff --git a/service/prefetch.py b/service/prefetch.py
index b16f52d40..6c45ffc63 100644
--- a/service/prefetch.py
+++ b/service/prefetch.py
@@ -23,6 +23,11 @@ import os
 import eos.types
 import eos.db.migration as migration
 from eos.db.saveddata.loadDefaultDatabaseValues import DefaultDatabaseValues
+from eos.db.saveddata.databaseRepair import DatabaseCleanup
+import logging
+
+logger = logging.getLogger(__name__)
+
 
 class PrefetchThread(threading.Thread):
     def run(self):
@@ -55,6 +60,14 @@ if os.path.isfile(config.saveDB):
     # Import default database values
     # Import values that must exist otherwise Pyfa breaks
     DefaultDatabaseValues.importRequiredDefaults()
+
+    logging.debug("Starting database validation.")
+    database_cleanup_instance = DatabaseCleanup()
+    database_cleanup_instance.OrphanedCharacterSkills(eos.db.saveddata_engine)
+    database_cleanup_instance.OrphanedFitCharacterIDs(eos.db.saveddata_engine)
+    database_cleanup_instance.OrphanedFitDamagePatterns(eos.db.saveddata_engine)
+    logging.debug("Completed database validation.")
+
 else:
     # If database does not exist, do not worry about migration. Simply
     # create and set version
@@ -67,4 +80,3 @@ else:
     DefaultDatabaseValues.importDamageProfileDefaults()
     # Import default values for target resist profiles
     DefaultDatabaseValues.importResistProfileDefaults()
-