Monday, October 27, 2008

Vista 64 bug - JMicron controller in ACHI messes up!

I have an ASUS P5W DH Deluxe running an Intel Core2Duo E6600 @ 2.4 Ghz. The mobo has a JMicron IDE controller (JMB36X) Driver version: Date: 12/5/2006 running one IDE drive, one SATA drive and one e-SATA drive.

At Random intervals, the hard drives connected to the JMicron controller become read only!! This is a very frustrating problem that only occurs With Vista x64.

There is a temporary workaround to this:

fsutil volume dismount X:

where X: is your driver letter.

The fsutil method described above does solve the problem sometimes, however it may need to be done multiple times to get success.


1. To use the eSATA drive, the controller must be set up in ACHI mode. The ACHI mode along with Vista 64 seems to be the cause of the problem
2. The drivers I am using are from ASUS's site. Upgrading to a newer JMicron driver from the JMicron site makes the problem worse (More than one drive becoming read only at the same time).

I hope this has been reported as a Vista 64 issue. Hope to see it resolved in Vista SP2.
I have posted this in the TechNet forum.


dividebyzero said...

I am having the exact same problem. I have Asus P5W DH, core 2 duo e6600 , oc to 3.2, 4gb ram, vista x64 . i have only one internal sata hdd connected to jmicron running in achi mode. when the system freezes, i captured memory.dmp using a ps2 keyboard , but i am not familiar with kernel mode debugging. so its not much useful. the problem happens whenever i tried to upload pics to flickr or tried to back up my system to whs server. did you find any other workaround other than fsuitil? i have updated all drivers to latest..still no luck.

Kartik said...

Hi dividebyzero

As of now there seems to be no fix other than fsutil. Why dont you try it?

Note that the latest drivers are not the best as I had more problems after upgrading the drivers - it was kind of a deadlock.

Keep me posted on what you find.

CricketFan said...

The newest jmicron driver solves this issue for good.

Download it from here:

Read the release notes here:

There is a specific mention to the read-only issue being fixed!

--From another user

dividebyzero said...

ok..i read about fsutil. there's a system freezes when this I cannot even use fsutil when it happens.I'm going to try vista sp2 beta..

dividebyzero said...

i tried latest whdl driver yesterday, and it didnt solve my issue..

Kartik said...

Hey did you try version 45 - that seems to work fine for me. Version 46 seems to be buggy again.

Patch said...

Hi, Just wanted to say thanks for this. I've been having this same issue intermittently for a while now.

Latest drivers haven't resolved (

Hadn't considered unmounting through fsutil so thanks for the idea.

Quick bit of powershell on start up checks for write and runs your fsutil command until it starts working again.

Saves me some bother.