The dreaded "Unrecognized database format": what to do?

Thirith

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Jun 9, 2009
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115
We've been starting to have problems with some of the databases at work. For no reason that I've been able to discern, some of them have started to produce the "Unrecognized database format" error that is frequently mentioned online. So far, I've always been able to recover the database by opening and repairing the backend, but it leaves us all somewhat worried, as we don't know if this will always work, added to which it is simply a hassle if the DB keeps getting corrupted.

Which is why I've been wondering if there are ways to reduce the chances of this happening that are open to us. Due to the way permissions are set up, some of the workarounds and fixes that I've read about are unlikely to happen (e.g. registry tweaks). What we can edit is the databases themselves, both back end and front end, and we can change our behaviours, e.g. not access the databases via remote desktop or closing Access before we take our laptops off the docking station and move onto a different network. No idea if any of this makes it less likely that the error will occur, though.

Is there anything we can feasibly do under these circumstances?
 

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stumac

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Jul 16, 2010
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471
Have you got a way of managing the front end versions to ensure all users are using the most up to date version? (assuming each user has their own FE) using different versions can be a major source for corruption. I have recently found corruption issues when users front end become bloated over a short period of time - something to do with temporary tables, to get round it I checked the compact and repair on close option for the front end which seems to have worked.

Also using different versions of Access may cause potential issues.

If your front end has a lot of code in it then the code itself may need de-compiled and recompiled periodically if you are making front end changes.

Switching networks while docking/undocking can be annoying (i.e. having to Ctrl, Alt Delete to get out of the application), however I haven't had a scenario where this has caused corruption issues.
 

Thirith

Board Regular
Joined
Jun 9, 2009
Messages
115
Thanks a lot for your reply; those are good starting points for me to look into.

We have some minor variation with the front ends; for instance, with one DB I've created filtered lists where the filters are personalised, and this week I've been working on some upgrades to the main form, so I had a test version of the front end with the upgrades in place. It's very minor stuff, though - renamed fields, a button or two to automatise some steps in the process, that kind of thing.

I don't really use temporary tables and I tend to have "Compact and repair" checked.

I don't think we have different versions of Access, but as this is handled centrally by IT it is just about possible. I will check with them.

I have to admit that I'm not entirely sure what you mean with respect to de- and recompiling the code. Compiling the code is not something I've consciously done; I thought that Access basically does that on the fly.
 

stumac

Active Member
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Jul 16, 2010
Messages
471
it is fine to have multiple FE's, however, it does mean that you need to release multiple if you make a fundamental change. for example you add in a new mandatory field to a table. All FE's that have a form editing this table need to be updated independently. I tend to keep the number of FE's to a maximum of 2 with the rest of the differences handled by access (i.e. access to forms, buttons etc).

Access itself may use temporary tables, however, if you are compacting on close this should be fine anyway.

Access does recompile when you open a form with code or run some code, however, decompiling it manually and recompiling it may be worth a shot to ensure your code is still clean. there is a lot about it on google, here is a link to a basic instruction on doing it:

https://accessdatabasetutorial.com/...t-decompiling-microsoft-access-databases-too/
 
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Thirith

Board Regular
Joined
Jun 9, 2009
Messages
115
Quick follow-up question: Does anyone here know whether it's generally possible to repair a database when the "Unrecognized database format" error occurs? I know it's impossible to answer the question conclusively, but from what I've found online the most common reason for the error is a Windows (or possibly Access) bug that hasn't been fixed yet. If in those cases a repair is generally possible, we'll definitely persist, but I have in the past suggested scrapping DBs that started producing the error early on simply because I didn't know whether there'd be any underlying problems that might end up with us losing the whole thing.
 

Thirith

Board Regular
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Jun 9, 2009
Messages
115
They do, yes. The files are largely the same; they mainly differ in terms of the filters set for various views, but that's pretty much it.
 

welshgasman

Well-known Member
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May 25, 2013
Messages
822
Ok, that is good.
It is just I have seen so many scenarios where the DB was split, but everyone was using a shortcut to the same FE. :(
 

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