RSView32 Derived Tags - Any Ideas?

I have a large RSView32 application which has been working for many years (with frequent updates and additions). This application includes a derived tag file which generates totals and percentage splits from a large number of values. This derived tag file has recently just stopped working. The activity log shows that the file starts normally and there is no indication of an error but the tags do not change from their initial value. We are using RSView32 V7.4 and have not made any changes to the affected file or any of the tags used within it. If anybody has any ideas I would be grateful to hear them.
Andybr

Usually when I've had problems with a derived tag file stopping it has been because there is a bad tag or statement within the file. Probably not what you wanted to hear but are you absolutely sure there hasn't been an unnoticed change to the derived tag file or to the tag database?

When you open the derived tag file editor the RSView menu above changes to let you configure how the file runs, frequency, etc. Check and make sure something didn't get changed there as well.