How to preserve identifierForVendor in ios after uninstalling ios app on device?

You may keep it in KeyChain

-(NSString *)getUniqueDeviceIdentifierAsString{ NSString *appName=[[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString*)kCFBundleNameKey]; NSString *strApplicationUUID = [SSKeychain passwordForService:appName account:@"incoding"]; if (strApplicationUUID == nil) {    strApplicationUUID  = [[[UIDevice currentDevice] identifierForVendor] UUIDString];    [SSKeychain setPassword:strApplicationUUID forService:appName account:@"incoding"]; } return strApplicationUUID;}

Generally, don't use identifierForVendor. Instead, use NSUUID to generate a custom UUID and store that in the keychain (because the keychain isn't deleted if the app is deleted and reinstalled).

Addition to @nerowolfe's answer.

SSKeychain uses kSecAttrSynchronizableAny as a default synchronization mode. You probably don't want identifierForVendor to be synced across multiple devices so here is a code:

// save identifierForVendor in keychain without syncNSError *error = nil;SSKeychainQuery *query = [[SSKeychainQuery alloc] init];query.service = @"your_service";query.account = @"your_account";query.password = [[[UIDevice currentDevice] identifierForVendor] UUIDString];query.synchronizationMode = SSKeychainQuerySynchronizationModeNo;[query save:&error];