diff --git a/Signal/src/AppDelegate.m b/Signal/src/AppDelegate.m
index 1607ffdd9..f537ff8aa 100644
--- a/Signal/src/AppDelegate.m
+++ b/Signal/src/AppDelegate.m
@@ -106,10 +106,10 @@ static NSString *const kURLHostVerifyPrefix             = @"verify";
 
     // We need to this _after_ we set up logging but _before_ we do
     // anything else.
-    [self ensureMigrationToSharedData];
+    [self ensureIsReadyForAppExtensions];
 
 #if RELEASE
-    // ensureMigrationToSharedData may have changed the state of the logging
+    // ensureIsReadyForAppExtensions may have changed the state of the logging
     // preference, so honor that change if necessary.
     if (loggingIsEnabled && !OWSPreferences.loggingIsEnabled) {
         [DebugLogger.sharedLogger disableFileLogging];
@@ -189,9 +189,9 @@ static NSString *const kURLHostVerifyPrefix             = @"verify";
     return YES;
 }
 
-- (void)ensureMigrationToSharedData
+- (void)ensureIsReadyForAppExtensions
 {
-    if ([OWSPreferences hasMigratedToSharedData]) {
+    if ([OWSPreferences isReadyForAppExtensions]) {
         return;
     }
 
@@ -201,7 +201,7 @@ static NSString *const kURLHostVerifyPrefix             = @"verify";
     [OWSProfileManager migrateToSharedData];
     [TSAttachmentStream migrateToSharedData];
 
-    [OWSPreferences setHasMigratedToSharedData:YES];
+    [OWSPreferences setIsReadyForAppExtensions:YES];
 }
 
 - (void)startupLogging
diff --git a/Signal/src/environment/OWSPreferences.h b/Signal/src/environment/OWSPreferences.h
index 822f9fe4d..6a0cb1882 100644
--- a/Signal/src/environment/OWSPreferences.h
+++ b/Signal/src/environment/OWSPreferences.h
@@ -27,8 +27,8 @@ extern NSString *const OWSPreferencesKeyEnableDebugLog;
 
 #pragma mark - Specific Preferences
 
-+ (BOOL)hasMigratedToSharedData;
-+ (void)setHasMigratedToSharedData:(BOOL)value;
++ (BOOL)isReadyForAppExtensions;
++ (void)setIsReadyForAppExtensions:(BOOL)value;
 
 - (BOOL)getHasSentAMessage;
 - (void)setHasSentAMessage:(BOOL)enabled;
diff --git a/Signal/src/environment/OWSPreferences.m b/Signal/src/environment/OWSPreferences.m
index c7fa02d3c..8548715f8 100644
--- a/Signal/src/environment/OWSPreferences.m
+++ b/Signal/src/environment/OWSPreferences.m
@@ -23,7 +23,7 @@ NSString *const OWSPreferencesKeyCallKitPrivacyEnabled = @"CallKitPrivacyEnabled
 NSString *const OWSPreferencesKeyCallsHideIPAddress = @"CallsHideIPAddress";
 NSString *const OWSPreferencesKeyHasDeclinedNoContactsView = @"hasDeclinedNoContactsView";
 NSString *const OWSPreferencesKeyIOSUpgradeNagVersion = @"iOSUpgradeNagVersion";
-NSString *const OWSPreferencesKey_HasMigratedToSharedData = @"hasMigratedToSharedData";
+NSString *const OWSPreferencesKey_IsReadyForAppExtensions = @"isReadyForAppExtensions";
 
 @implementation OWSPreferences
 
@@ -60,9 +60,9 @@ NSString *const OWSPreferencesKey_HasMigratedToSharedData = @"hasMigratedToShare
 
 #pragma mark - Specific Preferences
 
-+ (BOOL)hasMigratedToSharedData
++ (BOOL)isReadyForAppExtensions
 {
-    NSNumber *preference = [NSUserDefaults.appUserDefaults objectForKey:OWSPreferencesKey_HasMigratedToSharedData];
+    NSNumber *preference = [NSUserDefaults.appUserDefaults objectForKey:OWSPreferencesKey_IsReadyForAppExtensions];
 
     if (preference) {
         return [preference boolValue];
@@ -71,9 +71,9 @@ NSString *const OWSPreferencesKey_HasMigratedToSharedData = @"hasMigratedToShare
     }
 }
 
-+ (void)setHasMigratedToSharedData:(BOOL)value
++ (void)setIsReadyForAppExtensions:(BOOL)value
 {
-    [NSUserDefaults.appUserDefaults setObject:@(value) forKey:OWSPreferencesKey_HasMigratedToSharedData];
+    [NSUserDefaults.appUserDefaults setObject:@(value) forKey:OWSPreferencesKey_IsReadyForAppExtensions];
     [NSUserDefaults.appUserDefaults synchronize];
 }
 
diff --git a/SignalServiceKit/src/TSConstants.h b/SignalServiceKit/src/TSConstants.h
index cefd281a0..717e2e0fc 100644
--- a/SignalServiceKit/src/TSConstants.h
+++ b/SignalServiceKit/src/TSConstants.h
@@ -57,6 +57,8 @@ typedef enum { kSMSVerification, kPhoneNumberVerification } VerificationTranspor
 #define textSecureSetProfileNameAPIFormat @"v1/profile/name/%@"
 #define textSecureProfileAvatarFormAPI @"v1/profile/form/avatar"
 
+#define SignalApplicationGroup @"group.org.whispersystems.signal.group"
+
 #pragma mark Push RegistrationSpecific Constants
 typedef NS_ENUM(NSInteger, TSPushRegistrationError) {
     TSPushRegistrationErrorNetwork,
diff --git a/SignalServiceKit/src/Util/NSUserDefaults+OWS.m b/SignalServiceKit/src/Util/NSUserDefaults+OWS.m
index 1bff0e3e3..923ada8e1 100644
--- a/SignalServiceKit/src/Util/NSUserDefaults+OWS.m
+++ b/SignalServiceKit/src/Util/NSUserDefaults+OWS.m
@@ -3,6 +3,7 @@
 //
 
 #import "NSUserDefaults+OWS.h"
+#import "TSConstants.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -10,7 +11,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (NSUserDefaults *)appUserDefaults
 {
-    return [[NSUserDefaults alloc] initWithSuiteName:@"group.org.whispersystems.signal.group"];
+    return [[NSUserDefaults alloc] initWithSuiteName:SignalApplicationGroup];
 }
 
 + (void)migrateToSharedUserDefaults
diff --git a/SignalServiceKit/src/Util/OWSFileSystem.m b/SignalServiceKit/src/Util/OWSFileSystem.m
index 1d77559ad..551387b93 100644
--- a/SignalServiceKit/src/Util/OWSFileSystem.m
+++ b/SignalServiceKit/src/Util/OWSFileSystem.m
@@ -3,6 +3,7 @@
 //
 
 #import "OWSFileSystem.h"
+#import "TSConstants.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -38,8 +39,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (NSString *)appSharedDataDirectoryPath
 {
-    NSURL *groupContainerDirectoryURL = [[NSFileManager defaultManager]
-        containerURLForSecurityApplicationGroupIdentifier:@"group.org.whispersystems.signal.group"];
+    NSURL *groupContainerDirectoryURL =
+        [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:SignalApplicationGroup];
     return [groupContainerDirectoryURL path];
 }
 
@@ -52,7 +53,8 @@ NS_ASSUME_NONNULL_BEGIN
         return;
     }
     if ([fileManager fileExistsAtPath:newFilePath]) {
-        DDLogError(@"");
+        OWSFail(
+            @"%@ Can't move file from %@ to %@; destination already exists.", self.logTag, oldFilePath, newFilePath);
         return;
     }
     
@@ -62,11 +64,11 @@ NS_ASSUME_NONNULL_BEGIN
     BOOL success = [fileManager moveItemAtPath:oldFilePath toPath:newFilePath error:&error];
     if (!success || error) {
         NSString *errorDescription =
-        [NSString stringWithFormat:@"%@ Could not move database file from %@ to %@, error: %@",
-         self.logTag,
-         oldFilePath,
-         newFilePath,
-         error];
+            [NSString stringWithFormat:@"%@ Could not move file or directory from %@ to %@, error: %@",
+                      self.logTag,
+                      oldFilePath,
+                      newFilePath,
+                      error];
         OWSFail(@"%@", errorDescription);
         [NSException raise:exceptionName format:@"%@", errorDescription];
     }