Officeholidays ICS Calendar fails to import - One identified item in invalid format


most recent eMClient version 8, free license.

subscribing to ICS Calendars on Officeholidays always fails with an error:

1:46:43 Internet Calendars Web Calendar Synchronizing folder ‘/
11:46:43 Internet Calendars [Web Calendar] MailClient.Storage.Application.OperationException: Synchronizing folder ‘Internet Calendars/’ failed due to the following error: One of the identified items was in an invalid format.
—> System.FormatException: One of the identified items was in an invalid format.
at MailClient.VObject.CalendarReader.StringToDateTime(String value)
at MailClient.VObject.CalendarReader.LoadDateTimeValues(String encodedValue)
at MailClient.VObject.CalendarReader.LoadValues(ValueType type, Encoding encoding, Nullable1 separator) at MailClient.VObject.CalendarReader.LoadProperty(String line) at MailClient.VObject.CalendarReader.LoadFromReader(Calendar calendar) at MailClient.VObject.CalendarReader.LoadCalendar(Calendar calendar) at MailClient.VObject.Calendar..ctor(TextReader reader) at MailClient.Protocols.WebCal.WebCalCalendarSynchronizer.Synchronize(IItemSynchronizeContext1 synchronizeContext, Folder folder, CancellationToken cancellationToken)
at MailClient.Protocols.Common.ItemSynchronizer`2.<>c__DisplayClass37_1.b__6(WorkerStatus status, CancellationToken ct)
at MailClient.Protocols.WebCal.WebCalGenericCommand.Execute(WorkerStatus status)
— End of inner exception stack trace —

Could you please fix that, or at least give us a hint what to edit in .ics file so it would be parsed correctly with eMClient?

Monday 05 October 2020 :: 1250hrs (UTC +01:00)

Hi @aseg3

I have just successfully downloaded and installed from:
the file austria.ics
Unfortunately I don’t know the process that you went through.
Here is what I did:
WITH eMC in view (top left) Menu ->File ->Import ->iCalendar (.ics)
->Cut & Paste into top field ->
->In lower field ->Select folder ->Select Local Folders ->New Folder
->Enter name for new Folder ->Follow instructions

Personally I directly download *.ics files save them to my system and install
diectly from the calendar file, that way I always have a copy of the file,
if you choose to do this, instead importing from the site as above point
to the file you have downloaded.

¡Saludos desde la soleada España!



I’ve been trying out eM Client since this issue and it’s now a different kind. With Free License and Version 8, the initial adding of the Officeholidays .ics URL works, but later fails at synchronizing with error:

[Web Calendar]Synchronizing folder ‘Internet Calendars/Austria Holidays’ failed due to the following error: String ‘20210226T24607’ was not recognized as a valid DateTime.

Validating the .ics gives out warnings, but not errors:

So can you please fix this? It doesn’t seem like a huge thing to do, since the string looks in a reasonable format for a timestamp.

I know that the Austrian Holiday Calendar is an option to import, but i’d need a Slovenian calendar too (

Also deleting internet calendars is hard, since mostly you get an error that the “account is read-only”.

To delete an Internet Calendar, right-click on the calendar and choose Delete.