NAV 5.01 Client "freezed" (not responding)

Good Morning,

Since more than a month I try to find out a problem with a client which is from time to time no longer responding.

There is a third party PDF-printer and a third party DLL (automation) which is called from a job scheduler within a native Dynamics NAV 5.01 database. This job runs 7 days a week at the same time and calls the DLL (automation) which creates an ASCII-text index file and prepares the PDF-filename. The filename is stored in the server registry. Afterwards the posted invoice is read and printed. The PDF-printer retrieves the filename from the server registry and creates a PDF-file.

This job runs at one customer since months without any problems. At another customer the client gets “freezed” and the displayed windows are all white. There is no error message displayed, there is also nothing mentioned in the server event logs. The client has then to be cancelled.

Unfortunately I cannot force the error. It might be, that the job is running without any problems during several days. But it might also be, that the job does not respond the first time after a client restart. Sometimes the program stopped during the call of the DLL, but most of the time it stopped after the call of the DLL and just before or during the call of the report (report.runmodal).

I have absolutely no idea, how to find out the problem. Also Microsoft could not help.

Do you have any ideas? I slowly get crazy!

Both customers have a native NAV 5.01 database, build 29410. Both customers have Windows 2003 Servers.

Thank you very much, Beno!!!

Such behaviour means that Navision is very busy doing something, no time for even refreshing the window - that for it becomes “white”. Earlier I’ve seen this during restore of backup in Native DB, other very resource consuming tasks --or waitng for some lock to be released-- can cause it, too.

What you described seems not to have anything in common with situations I mentioned, but anyway - you could start with checking in TaskManager the resource usage of Navision executable - if a program is “hanged”, this usage drops to zero (except Memory). If it is high - dig for reasons in code.

Another possibility - as server is involved, look at network load. This is more possible cause, as that could explain why “hangs” are irregular and unpredictable, and why one customer has never problems, but the another has them without any reason.
Examine what happens with this client’s network load, unsuccessfuly designed network infrastructure can bring it down even with not so big user count. Maybe they’re still using prehistorical hubs instead of switches? TCP/IP protocol is built so, that when 80% of maximum theoretical throughput is reached, traffic practically stalls, as packet collision reaches almost 100%, packets are resent over and over again, thus causing collision avalanche.