PH not archiving tag data after ES compile with memory reset

Hello all,

I am experiencing a frustrating archiving problem with a PCS7 V9.1 SP2 UC07 running with redundant OS server pair and non-redundant PH server. I recently performed an OS full compile with memory reset on the ES, and did a full download to both OS servers. After the OS servers restarted and synched, I noticed the PH was archiving alarm data, but not archiving tag data.

After some investigation, I found that PH was indicating "Needed" under Tag Recovery. From time to time I would see the state change to "Running" and then back to "Needed". It appears the PH was unable to complete the synch needed to engage tag archiving. It was an odd observation, as the OS servers were synched, the alarm data indicated "NoRecovery" and was working correctly.

So far I have tried everything I can think of to get this to work, but I can't find a solution, as follows:

1. Tried clearing SFCache on both OS servers.

2. Tried resetting alarm and tag logs on the OS servers.

3. Tried doing multiple full compiles and downloads to servers.

4. Tried restarting all the machines in different sequences.

5. Lastly, re-created the PH database. This last step actually temporarily solved the problem. Upon initial startup and synch of the OS servers, post PH database reset, the PH synched and was able to log both alarm and tag data. Unfortunately as soon as I restarted the OS servers, the same issue re-appeared and tag data stopped logging.

Has anyone experiencing something like this in the past, as I am somewhat at a loss of where to go from here?

Thanks a bunch for any help!

Update:

As of yesterday, Siemens has posted an update: https://support.industry.siemens.com/cs/document/109812242/simatic-pcs-7-v9-1-sp2-software-updates?dti=0&lc=en-WW 

It appears the WinCC update related on May 6, 2025, which is WinCC V7.5 SP2 Upd20 is not compatible with PH. Therefore anyone with such installations should avoid installing such an update till further notice.

It is frustrating and hard to believe that updates like this are coming out. In our case we now have a broken plant, which requires substantial effort to restore to a working state. Siemens, please do a much better job with your patches going forward. We have faced numerous such issues over the years, where the patch fundamentally breaks a core component of the system.

Update: As a few days ago, Siemens has received a workaround patch to resolve PH archiving issues. We have so far tested this patch, and found it has resolved these problems. As of now, this is a by request only patch, for which you have to contact support. My understanding is that an official PH update will be released at a later time.