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Unrecognized database format "XXX.mdb"

Posted on 2013-11-18
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Last Modified: 2013-11-21
Hi,
 
  I have developed a MS Access database, went corrupted and could not even repair using ACCESS own "Compact and Repair" or JetUtil.

  That said, I ended up restoring it from the backup device and all is good.
  But the reason I am posting this question is:

 (1) When users are using the database on a local network, it is fine.
      But this has happened before when users connected to the database via VPN tunnel.
 (2) The database file size was 6.7MB, but this morning the size was 412K and there was .ldb file as well.  

  My question is how the database file size can change so drastically, let alone getting corrupted?

Thanks.
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Question by:sglee
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by:jerryb30
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Is this a multi-user db? Is there a local front end?
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by:sglee
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It is a multi-user system, but 99% of the time, there is only one person entering data - one record/row a day on average.
I created front end and back end once and performed the test, but there were about the same once we get into "data entry screen" and start looking up the record or move the record to prev or next. So for my own convenience it just combined them into one MDB file.
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Scott McDaniel (Microsoft Access MVP - EE MVE ) earned 500 total points
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But this has happened before when users connected to the database via VPN tunnel.
Access does not work well with VPNs, and there's not much you can do to make things better.
The database file size was 6.7MB, but this morning the size was 412K and there was .ldb file as well.  
I'd be very concerned with a database that went from 6.7 mb down to 412k, and would immediately stop using the VPN. The .ldb file is a lockfile, and it's created every time someone opens the database, so that isn't a concern.

If you have offsite users the best way to manage them is through some sort of remote desktop setup. Often this entails setting up an RDS Server, which requires you to purchase server software.
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by:sglee
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@LSMConsulting
Have you seen the database size reduced like that from the original size with corruption?
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Yes, and in most cases it's catastrophic (better keep good backups).

The issue, however, is the VPN. You're playing with fire trying to run an Access database across a VPN. It's far too unstable, and disconnects/connects too often for it to be reliable.
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by:sglee
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Do you think if I split the database and keep  Front End.mdb (forms, reports .. etc)  on each workstation and Back End.mdb (tables, queries) on the File Server, it will solve the problem?
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Do you think if I split the database and keep  Front End.mdb (forms, reports .. etc)  on each workstation and Back End.mdb (tables, queries) on the File Server, it will solve the problem?
If you keep the VPN in the mix then no, it won't solve the problem. It may very well reduce the frequency of corruption, but if you have users connecting over VPN then corruption is virtually assured. As I mentioned earlier, the only reliable way to support offsite users with an Access application is to use some sort of remote desktop setup.

That said, you should ALWAYS split a database, and each user should have their own separate copy of the FE, and all of those FEs should connect to the same BE.
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