Error message after updating iphone
The system effectively becomes unaware of the application until mass storage is disabled and the external storage is remounted on the device. When you enable USB mass storage to share files with your computer (or otherwise unmounts or removes the external storage), any application installed on the external storage and currently running is killed.
To check if an application is linked or not use Link2SD application. I am getting read-only file system error and can not link any app anymore.
And, disadvantage is that, obviously, it requires root privilege and a second partition on your SD card. If you have a custom recovery installed (Clockwork Mod or Amon Ra) on your phone you can use it to create a second partition on your SD card. But when I install a new app I see reduction on the internal storage even if the app is linked. Link2SD does not link application's private data files that are located in /data/data directory, they remain in the internal storage.
Link2SD allows you to run all of your "SD apps" even when mounted to your computer as a disk drive. Most probably your rom has already builtin a2sd, try to disable a2sd on your ROM. I succesfull set up Link2SD and linked most of my applications to SD card and enabled "auto link".
First advantage is that it can free up more space from the internal storage compared to native apps2sd method because it moves the dex file as well.
Link2SDLink2SD moves apk dex lib files of the application to the second partition and creates symbolic links in the original locations on internal storage.
Native apps2sd Starting with Android 2.2 (Froyo) Google introduced native apps2SD.