I recently tried to do an offine defrag of one of my client's Exchange Server 2003 SP2 databases...It kept failing with the "unable to find the callback library jcb.dll (or one of it's dependencies)." error messages. I tried all options...copying the jcb.dll file from another exchange server, using the one i found in the symantec backup exec folder...nothing worked. The amount of space that can be recovered is now nearly 5GB (of a 40GB store) so it's really important to me that i can run this. Nobody has seemed to figure this out yet.

That amount of space shouldn't be that important to you, actually. You'll probably find that 5GB beint eaten up almost immediately after running the defrag.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

You are doing an offline defrag for a gain of 5gb? Is disk space an issue? I wouldn't be able to justify the downtime for that kind of gain. 40gb is a tiny store, it will not be causing a problem from a performance point of view. If you were trying to recover 20gb then I might think about it, but not 5gb. You will use that space up in a few months in most systems. As a rule, I don't even consider an offline defrag unless I am going to gain at least 50% of the space back AND there is no possibility that space will be reused. That would be after an archiving product was introduced normally. Otherwise it isn't worth the downtime. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

Thanks for the advice (on whether or not i should actually do one) but that's not why i am posting this. i am still looking for an answer to the question as to how to resolve the error message. This is a very small office so i will not use 5GB of space immediately after the defrag is completed. There is archiving taking place so when i am able to resolve this issue and DO one, the amount of space i will be able to recover will be more.

Quote: “I tried all options...copying the jcb.dll file from another exchange server” Does the issue only happen to single database? The same issue doesn’t reproduce on that “another exchange server”, right? Please make sure that “another exchange server” is in the same service pack level as the problematic server The symptom can be caused by a lack of virtual memory that can be solved by implementing the /3GB switch (KB 823440). Please reboot the server after add the parameters, and check if the issue has been fixed James Luo TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Thanks for the advice (on whether or not i should actually do one) but that's not why i am posting this. i am still looking for an answer to the question as to how to resolve the error message. This is a very small office so i will not use 5GB of space immediately after the defrag is completed. There is archiving taking place so when i am able to resolve this issue and DO one, the amount of space i will be able to recover will be more. So this small office can cope without email for almost two days then? You are aware that an offline defrag takes an extended period of time? Depending on the hardware it can be as slow as 1gb per hour. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

IS this SBS ? if it is put /3gb switch in the boot.ini . degrag the database and remove the /3gb i faced the exct same issue around 6 months ago in one my small business custumer and above workaround workedDhruv

Simon... Yes i am aware how long an offline defrag might take. The hardware is plenty fast enough so it won't take 1GB/hr. I have secondary email hosting in place so it shouldn't be an issue how long the email was down. Nothing was going to be lost. I was also doing this during the holidays when the office was closed. James and Dhruv: Yes it is an SBS box. The file i pulled from another server had the same SP. I restored the original file. Since it is an SBS box, i don't have the /3GB switch in place but if you are saying to only leave it there long enough to do the defrag, i will give that a try.

/3Gb will work for sure,,, :) remember to remove it after defrag is done Dhruv

How's the issue currently? Any further information?Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.