>Hi All,
>
>The app is multiuser. There is a situation that all get an automated instruction to close down after 30 seconds. When closing down, a logtable is opened, a record of the user is updated and finally it is closed. I guess that all machines try this after exactly the 30 seconds (the user can do it earlier). The table is opened with:
>

USE 'thetable' SHARED AGAIN

No inserts are done, only 'owned' records are updated. Also no one has it opened exclusive.
>
>Nevertheless, some (out of let's say 100) get a File Access Denied error 1705. Is this to be anticipated behavior? What can I do best? Use a do-while?

If you have a "logged in" table with each process holding a lock on its own record, you could try to use this table to que the access to the log table. Or send the automated shutdown to the next machine AFTER the log is written and the RLOCK on the login record is released.

Had something similar in the routines preparing for schema changes to backend tables with an app of a couple of hundred tables...
Also used status fields in the login table:

first block all unlocked logins
loop
  send takedown notices
update
unblock login table