Database error when loading the Stage 1 and 2 .d2i


I am having the following issues that occurs sometimes when restarting the service. It seams that the .d2i loading process fail, displaying the following error message:
“[RTAC] Connection attempt failed: The given key was not present in the dictionary”

RTAC is an instance like PPA.

I was able to solve the problem by removing some of the Stage 1 and Stage 2 .d2i files from the database. The storing process goes back to normal after removing those files however I think I am removing more files that I need.

Did anybody have the same issue?

Thanks in advance


Are your archive files and your staging files on the same drive? Then secondly, what is the disk space remaining on the target drive(s)?

We may need to adjust a few more parameters.


Both Stages and Archives are in the same drive (D:) in different folders.

The target drive is

RTAC instance
Connection String :ArchiveDirectories={E:\openHistorian\Archive}; WorkingDirectory=E:S\openHistorian\WorkingDirectory

A few things you can try to adjust:

  1. ArchiveCurtailmentInterval, units in seconds, defines how often the system attempts to delete old files. You might want to run this timer 4 times per day, or a setting like 21600, since your drive is fairly small.
  2. DesiredRemainingSpace, units in GigaBytes, defines how much remaining space to “leave” on a drive, i.e., when to consider the drive full. The default value here is 500, already larger than your entire drive size. This is likely the primary issue, i.e., openHistorian considers your archive folder already full so it won’t roll over into this folder. Try setting the value to something more reasonable for your drive size, e.g., 20.
  3. MaximumArchiveDays, units in days, defines the maximum data time span for archived data. You will need to adjust this parameter based on how much data you archiving per day. You want to make sure max archive days can still leave enough desired space on drive per DesiredRemainingSpace setting.

Also, you setting for WorkingDirectory=E:S\openHistorian\WorkingDirectory may be OK, it just looks a little weird to me, I am thinking this should be: WorkingDirectory=E:\S\openHistorian\WorkingDirectory (backslash after E:)

And finally, you have probably already crossed the “rights” issues for folders, i.e., making sure openHistorian service (by default local account NT SERVICE\openHistorian) has read/write access to all configured folders.

Hope that helps!