diff --git a/.idea/misc.xml b/.idea/misc.xml
index 47eabe0..6faa303 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -24,7 +24,7 @@
       </value>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="JDK" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" default="true" project-jdk-name="JDK" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
   <component name="ProjectType">
diff --git a/app/src/main/java/us/spotco/malwarescanner/Database.java b/app/src/main/java/us/spotco/malwarescanner/Database.java
index 917142f..9e39b4c 100644
--- a/app/src/main/java/us/spotco/malwarescanner/Database.java
+++ b/app/src/main/java/us/spotco/malwarescanner/Database.java
@@ -33,9 +33,9 @@ public class Database {
 
         signatureDatabases.add(new SignatureDatabase("https://spotco.us/clamav-main.hdb", "clamav-main.hdb"));
         signatureDatabases.add(new SignatureDatabase("https://spotco.us/clamav-main.hsb", "clamav-main.hsb"));
-        signatureDatabases.add(new SignatureDatabase("http://clamav.bofhland.org/bofhland_malware_attach.hdb", "bofhland_malware_attach.hdb"));
-        signatureDatabases.add(new SignatureDatabase("http://cdn.malware.expert/malware.expert.hdb", "malware.expert.hdb"));
-        signatureDatabases.add(new SignatureDatabase("http://cdn.rfxn.com/downloads/rfxn.hdb", "rfxn.hdb"));
+        //signatureDatabases.add(new SignatureDatabase("http://clamav.bofhland.org/bofhland_malware_attach.hdb", "bofhland_malware_attach.hdb"));
+        //signatureDatabases.add(new SignatureDatabase("http://cdn.malware.expert/malware.expert.hdb", "malware.expert.hdb"));
+        //signatureDatabases.add(new SignatureDatabase("http://cdn.rfxn.com/downloads/rfxn.hdb", "rfxn.hdb"));
     }
 
     public static boolean doesDatabaseExist() {
@@ -49,9 +49,9 @@ public class Database {
     }
 
     public static void loadDatabase(ArrayList<SignatureDatabase> signatureDatabases) {
-        signaturesMD5 = new HashMap<String, String>();
-        signaturesSHA1 = new HashMap<String, String>();
-        signaturesSHA256 = new HashMap<String, String>();
+        signaturesMD5.clear();
+        signaturesSHA1.clear();
+        signaturesSHA256.clear();
         System.gc();
         for (SignatureDatabase database : signatureDatabases) {
             File databaseLocation = new File(databasePath + "/" + database.getName());
diff --git a/app/src/main/java/us/spotco/malwarescanner/MalwareScanner.java b/app/src/main/java/us/spotco/malwarescanner/MalwareScanner.java
index 44250a0..fe29675 100644
--- a/app/src/main/java/us/spotco/malwarescanner/MalwareScanner.java
+++ b/app/src/main/java/us/spotco/malwarescanner/MalwareScanner.java
@@ -12,7 +12,11 @@ import com.google.common.hash.Hashing;
 import com.google.common.io.Files;
 
 import java.io.File;
+import java.io.FileInputStream;
 import java.io.IOException;
+import java.io.InputStream;
+import java.math.BigInteger;
+import java.security.MessageDigest;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
@@ -20,16 +24,20 @@ import java.util.Set;
 
 public class MalwareScanner {
 
-    private Context context = null;
-    private TextView log = null;
-    private AsyncTask<Boolean, String, String> malwareScannerTask = null;
+    private static Context context = null;
+    private static TextView log = null;
+    private static AsyncTask<Boolean, String, String> malwareScannerTask = null;
+
+    private static HashMap<String, File> fileHashesMD5 = new HashMap<String, File>();
+    private static HashMap<String, File> fileHashesSHA1 = new HashMap<String, File>();
+    private static HashMap<String, File> fileHashesSHA256 = new HashMap<String, File>();
 
     public MalwareScanner(Context context, TextView log) {
         this.context = context;
         this.log = log;
     }
 
-    public void startScanner(boolean scanSystem, boolean scanApps, boolean scanInternal, boolean scanExternal) {
+    public static void startScanner(boolean scanSystem, boolean scanApps, boolean scanInternal, boolean scanExternal) {
         if(Database.doesDatabaseExist()) {
             malwareScannerTask = new MalwareScannerTask().execute(scanSystem, scanApps, scanInternal, scanExternal);
         } else {
@@ -48,11 +56,14 @@ public class MalwareScanner {
         return malwareScannerTask.getStatus().equals(AsyncTask.Status.PENDING) || malwareScannerTask.getStatus().equals(AsyncTask.Status.RUNNING);
     }
 
-    public class MalwareScannerTask extends AsyncTask<Boolean, String, String> {
+    public static class MalwareScannerTask extends AsyncTask<Boolean, String, String> {
 
         @Override
         protected void onPreExecute() {
             log.append("Initiating scan...\n");
+            fileHashesMD5.clear();
+            fileHashesSHA1.clear();
+            fileHashesSHA256.clear();
         }
 
         @Override
@@ -85,20 +96,19 @@ public class MalwareScanner {
             }
             publishProgress(filesToScan.size() + " files pending scan");
 
-            HashMap<String, File> fileHashesMD5 = new HashMap<String, File>();
-            HashMap<String, File> fileHashesSHA1 = new HashMap<String, File>();
-            HashMap<String, File> fileHashesSHA256 = new HashMap<String, File>();
-
             Database.loadDatabase(Database.signatureDatabases);
             publishProgress("Loaded " + Database.signaturesMD5.size() + " MD5 signatures");
             publishProgress("Loaded " + Database.signaturesSHA1.size() + " SHA-1 signatures");
             publishProgress("Loaded " + Database.signaturesSHA256.size() + " SHA-256 signatures\n");
 
+            publishProgress("Hashing files...");
+            for (File file : filesToScan) {
+                getFileHashes(file);
+            }
+            publishProgress("Calculated MD5/SHA-1/SHA-256 hashes for all files\n");
+
             if (Database.signaturesMD5.size() > 0) {
-                for (File file : filesToScan) {
-                    fileHashesMD5.put(getFileHashSum(file, Hashing.md5()), file);
-                }
-                publishProgress("Calculated MD5 hashes for all files");
+
                 for (Map.Entry<String, File> file : fileHashesMD5.entrySet()) {
                     String result = Database.checkInDatabase(file.getKey());
                     if (result != null) {
@@ -111,10 +121,6 @@ public class MalwareScanner {
             }
 
             if (Database.signaturesSHA1.size() > 0) {
-                for (File file : filesToScan) {
-                    fileHashesSHA1.put(getFileHashSum(file, Hashing.sha1()), file);
-                }
-                publishProgress("Calculated SHA-1 hashes for all files");
                 for (Map.Entry<String, File> file : fileHashesSHA1.entrySet()) {
                     String result = Database.checkInDatabase(file.getKey());
                     if (result != null) {
@@ -127,9 +133,6 @@ public class MalwareScanner {
             }
 
             if (Database.signaturesSHA256.size() > 0) {
-                for (File file : filesToScan) {
-                    fileHashesSHA256.put(getFileHashSum(file, Hashing.sha256()), file);
-                }
                 publishProgress("Calculated SHA-256 hashes for all files");
                 for (Map.Entry<String, File> file : fileHashesSHA256.entrySet()) {
                     String result = Database.checkInDatabase(file.getKey());
@@ -159,7 +162,7 @@ public class MalwareScanner {
 
     }
 
-    private Set<File> getFilesRecursive(File root) {
+    private static Set<File> getFilesRecursive(File root) {
         Set<File> filesAll = new HashSet<>();
 
         File[] files = root.listFiles();
@@ -179,13 +182,34 @@ public class MalwareScanner {
         return filesAll;
     }
 
-    private String getFileHashSum(File file, HashFunction hash) {
+    private static void getFileHashes(File file) {
         try {
-            return Files.asByteSource(file).hash(hash).toString();
-        } catch (IOException e) {
+            InputStream fis =  new FileInputStream(file);
+
+            byte[] buffer = new byte[4096];
+            int numRead;
+
+            MessageDigest digestMD5 = MessageDigest.getInstance("MD5");
+            MessageDigest digestSHA1 = MessageDigest.getInstance("SHA-1");
+            MessageDigest digestSHA256 = MessageDigest.getInstance("SHA-256");
+
+            do {
+                numRead = fis.read(buffer);
+                if(numRead > 0) {
+                    digestMD5.update(buffer, 0, numRead);
+                    digestSHA1.update(buffer, 0, numRead);
+                    digestSHA256.update(buffer, 0, numRead);
+                }
+            } while (numRead != -1);
+
+            fis.close();
+
+            fileHashesMD5.put(String.format("%032x", new BigInteger(1, digestMD5.digest())), file);
+            fileHashesSHA1.put(String.format("%032x", new BigInteger(1, digestSHA1.digest())), file);
+            fileHashesSHA256.put(String.format( "%064x", new BigInteger(1, digestSHA256.digest())), file);
+        } catch (Exception e) {
             e.printStackTrace();
         }
-        return null;
     }
 
 }