External SD memory vanished

[Turnstyle]

- Model of your phone (T989)
- Type of connection (WiFi)
- MPE-version (i.e. MPE 1.8.4)
- Windows version (i.e. WinXP-SP3)
and at last in some cases it would help if you post your
- firmware version (4.0.4)

Log File:
Logdatei MyPhoneExplorer
************************
Programmversion: 1.8.4
Datum: 8/6/2013

18:06:12.37 Setting Port: 999
18:06:12.37 Setting Baud: 115200
18:06:12.37 Avaiable Ports: COM3=\Device\ssudmdm0000;
18:06:12.37 Main Load frmSplash
18:06:12.53 Load frmSplash...
18:06:12.53 Show splash...
18:06:12.60 frmSplash geladen
18:06:13.88 Hauptfenster wird geladen
18:06:14.18 Sidebar fertig geladen
18:06:14.32 UC SMS wird geladen
18:06:14.37 UC Phonebook wird geladen
18:06:14.43 UC Phonebook fertig geladen
18:06:14.43 UC Calls wird geladen
18:06:14.46 UC Organizer wird geladen
18:06:14.56 Organizer initiated
18:06:14.59 Startpage=1
.
.
.

New to MPE & working out well, so far. Using mostly to sync calendar from T-bird, some file management (as below) not syncing contacts, yet.
External memory was showing up fine.
Setup custom sync for music files folder in ext. memory.
Working fine.
All of a sudden, external SD card not showing today.
Tried restarting software, both on the PC and the phone.
I can still access ext. memory with ES file explorer (app) on phone.
I have now stopped MPE on both the PC and the phone and am trying to access the ext. mem. using USB. Windows explorer is showing corrupted file system message.
Rebooted phone. Now ext. memory there, no folders.
Bad SD card?
Any experience with Samsung Galaxy S2? File system problems?
Thanks for any help.

[FJ]

I don't think that this issue is related to MyPhoneExplorer. remove and insert your memory card. if this does not help then test the behaviour with another sd card