We're sorry Aspose doesn't work properply without JavaScript enabled.

Free Support Forum - aspose.com

An invalid character was found in the Base-64 stream

I’m trying to retreive the list of message on an Exchange server and getting this exception, is there any work around ?

System.FormatException:An invalid character was found in the Base-64 stream.

at ?.?.(Byte[] , Int32 , Int32 )

at ?..(String , String , String )

at ?..(String )

at ?..??(? , ImapMessageInfo )

at ?..??(?[] , String )

at ?..??(? , String , Int32 )

at ?.?.?(Int32 , Int32 )

at Aspose.Email.Imap.ImapClient.ListMessages(Int32 maxNumberOfMessages)


Mathieu Vanier

Hi Mathieu,

Could you please share with us which version of Aspose.Email for .NET are you using? I have tried to reproduce this issue at my end using the latest version of Aspose.Email for .NET 3.9.0 and was unable to get success.

From our past experience, we have observed that such issue may arise due to particular message in the mailbox. Therefore, we need your assistance to reproduce this issue at our end and fix it. You can provide us with a test account containing sample test message that gives rise to such an issue. Alternatively, if you could identify such a message and provide us with that, we can add it to our exchange mailbox for testing and investigate the issue at our end.

We regret the inconvenience you have faced and appreciate your cooperation in this regard.

I was using version 3.5 but you need a faulty email in the inbox. I cannot provide it, because when I go read the mail manually with Outlook the application corrects the error. That specific email was requesting a read confirmation.
In other cases I have a problem to read a specific email. I can read the list of email but I get an error when I try to get the email by it’s id. We have a work around for this case. I can move the mail to another directory in the mailbox and the owner of the mailbox is notified and goes manually move the mail with Outlook so the problem is solved.


Mathieu Vanier

Hi Mathieu,

Thank you for sharing the feedback and its good to know that your problem is solved. Please feel free to write to us in case you have any additional query/inquiry with respect to Aspose.Email. We’ll be glad to assist you further.