Jccomo, I apologize for my delay in responding.
Originally Posted by jccomo
We also have noted the Pre/Google Calendar sync doesn't seem to handle large amounts of past data well. In particular, people who load up with years of data. In cases we've investigated people have 3000-5000 entries spanning 5-12 years.
In our testing we have not found a hard limit. Nor have we identified any particular type of data that is the culprit. The general rule appears to be that the data needs to be limited to about the last three years or so. As you note, single appointments work fine back 10 years or more. So it appears to be a "size of data" problem, and not specifically a "this date doesn't work" problem.
CompanionLink has a setting that you can control the number of days back. I suggest moving it to "last 90 days" to insure that it all works fine. Use this for a day. Then when you have time, push back about six months, and run it for a day again. Keep pushing back six months at a time, and keep an eye out for failure. Failure can exhibit either by not synchronizing old data, as in your case, or not synchronizing new data, which other people have reported.
I would not go back farther than 1000 days, which is about three years. I have a theory that it's related to the 2005 Energy Policy Act which took effect March 2007. You will recall in that year Daylight time (DST) in the US moved from the first Sunday of April, to the first Sunday in March, yielding a big pain for makers of calendar software, in return for zero energy savings. Some software programmed after 2007 may not be handling DST correctly for events prior to March 2007. I suspect the problem is related to repeating events that either Span 2007, or are prior to 2007, that span a period of Standard and Daylight time. Perhaps some error in conversion for these long past events is causing the internal ActiveSync Client to stall.
I hope this information helps.
Wayland Bruns, CTO
CompanionLink Software, Inc.