Data in the Experience Analytics or Experience Profile applications might be missing when using xDB Cloud 1.0 or 2.0. This might happen if the on-premise server where the reports are shown (typically CM) is running with one .NET version (for example 4.7.2) and xDB Cloud Reporting service has another one (for example 4.5). Here are a few examples of errors in the on-premise server logs:
ERROR Member '_compareInfo' was not found. Exception: System.Runtime.Serialization.SerializationException Message: Member '_compareInfo' was not found. Source: mscorlib at Sitecore.Analytics.Reporting.Datasources.Remote.RemoteReportDataSourceProxy.GetData(ReportDataQuery query) at Sitecore.Analytics.Reporting.ReportDataProvider.ExecuteQueryWithCache(ReportDataQuery query, ReportDataSource dataSource, CachingPolicy cachingPolicy) ...
ERROR Error in line 18 position 13. 'EndElement' 'Comparer' from namespace '' is not expected. Expecting element '_compareInfo'. Exception: System.Runtime.Serialization.SerializationException Message: Error in line 18 position 13. 'EndElement' 'Comparer' from namespace '' is not expected. Expecting element '_compareInfo'. Source: System.Runtime.Serialization at Sitecore.Analytics.Reporting.Datasources.Remote.RemoteReportDataSourceProxy.GetData(ReportDataQuery query) at Sitecore.Analytics.Reporting.ReportDataProvider.ExecuteQueryWithCache(ReportDataQuery query, ReportDataSource dataSource, CachingPolicy cachingPolicy) ...
This affects only the displaying of the data, which is caused by different XML serialization algorithms on the on-premise and xDB Cloud Reporting servers. No data loss is expected. You can find more technical details here:
https://github.com/dotnet/corefx/issues/30415.
Note: we recommend you to apply the following solution only if you have the error with the mentioned stack trace.
Install the latest .NET framework on the server where the reports are shown, typically CM: https://www.microsoft.com/net/download/dotnet-framework-runtime.
If this does not help, contact Sitecore Support.