eM Client gives me sync errors

em Client gibt mir mehrfach je Tag bei der Benutzung des Clients folgenden Fehler aus:

"Das Synchronisieren des Ordners ist fehlgeschlagen mit folgendem Fehler: Das Objekt des Typs ‘System.DBNull’ kann nicht in Typ ‘System.IComparable’ umgewandelt werden."

Ich verstehe nicht wirklich, was er mir damit sagen möchte … Ich kann nicht mal sagen, was der Auslöser ist oder seit wann es besteht.

Kann mir jemand bitte helfen?

VG Sandra

Hi Sandra, what version of eM Client are you currently using on your computer, can you please check for the exact version number in Help > About?
What mail service are you using with eM Client? Can you also make a screenshot of the error and post it here on the forum?

Thank you.


Hi Paul,

thanks for your reply - I just saw it…

I am using version 6.0.21040.0 of eM Client with Windows 8 and a Gmail account
and the screenshot of the error:

Hi again Sandra, what do you mean by a “Windows 8” account? Is that an Outlook or Exchange account? Can you make a screenshot of your account settings from Tools > Accounts > Your other account > IMAP?

Or try to right click the account in the left pane and select Properties > Repair and click on the “Repair” button.

Hope this helps,


I meant my PC OS uses Windows 8.
I set my gmail account in the eM Client as
Host imap.gmail.com,
Port 993

Host smtp.gmail.com
Port 587

I tried the Repair option, but it didn ́t help.

greetings Sandra

Hi again Sandra, can you please update eM Client to this release and check if the issue persists, http://www.emclient.com/dist/v6.0.21289/setup.msi ? If it does, please switch to the “Log” tab when the error occurs, copy the content of the log and post it here on the forum.

Thank you,

I updated and the error still occurs but unfortuantely I can ́t find the “Log” tab?
Can you please assist?

Or do you mean the screenshot above the section “Protokoll”?

I hope this is the right part:

13:51:55   MailExceptions.OperationException: Das Synchronisieren des Ordner ‘[email protected]/[email protected]/’ ist fehlgeschlagen mit folgendem Fehler: Das Objekt des Typs “System.DBNull” kann nicht in Typ “System.IComparable” umgewandelt werden. —> System.InvalidCastException: Das Objekt des Typs “System.DBNull” kann nicht in Typ “System.IComparable” umgewandelt werden.13:51:55    bei MailClient.Storage.Data.SQLite.DbRepository1.FindOids(QueryCondition condition, CancellationToken cancellationToken, SortField[] sortKeys) 13:51:55    bei MailClient.Protocols.Common.ItemSynchronizeContext2.Synchronize[T](SynchronizationType synchronizationType, IEnumerable1 items, Func2 getUniqueId, Func3 hasChanged, Func2 isDeleted, Func2 convertItems, Action2 updateItem)
13:51:55    bei MailClient.Protocols.Gdata.CalendarItemSynchronizer.Synchronize(IItemSynchronizeContext1 synchronizeContext, Folder folder, CancellationToken cancellationToken) 13:51:55 &nbsp; &nbsp;bei MailClient.Protocols.Common.ItemSynchronizer2.<>c__DisplayClass30.<>c__DisplayClass35.b__2c(WorkerStatus status, CancellationToken cancellationToken)
13:51:55 bei MailClient.Protocols.Gdata.GenericGapiCommand.Execute(WorkerStatus status)
13:51:55 — Ende der internen Ausnahmestapelüberwachung —
13:51:55 bei MailClient.Protocols.Gdata.GenericGapiCommand.Execute(WorkerStatus status)
13:51:55 bei MailClient.Commands.Command.Process(WorkerStatus status)

Hi again Sandra, it seems like this might be a database issue, can you please try to disable the account in eM Client and create the account from scratch using the automatic setup? If this issue reoccurs, please let us know.

Thank you,

Hi Paul, till now it works with disableing the first account and setting it up again. 
I hope it stays like that :slight_smile:

If not, I will write here

Have a nice day and christmas holidays soon!

Hi again, glad it works, please make sure to let us know if you come across any other issues or questions about the application, we’ll be happy to help.

Thank you,