Sync - Nullable object must have a value

Hi,

There was a problem with the Outlook/Office365 synchronisation that started recently. It started to give errors with a message like "Nullable object..."

We have investigated it and it seems Microsoft created a bug in their public Outlook API.

We have created a fix/workaround in the software, please update to the latest OneCalendar version from the store to resolve this issue:
- Windows OneCalendar version 2023.310.1.0 or higher
- Android OneCalendar version 4.3.5 or higher
- iOS OneCalendar version 4.4 or higher
- macOS OneCalendar version 4.4 or higher

Sorry for any inconvenience.

Have a good day!

OneCalendar Team

I have been facing the same issue for a couple of days now. I tried unlinking and linking the account, didn't work.

Hi,

This is a problem that started recently. We have investigated it and it seems Microsoft created a bug in their Outlook API. We have reported it to them and we are currently trying to create a solution/workaround as soon as possible.

Sorry for any inconvenience.

I have the same problem. Please solve this

Same issue

Same problem here. Used this app for years, recently decided to purchase. For me it weirdly shows half a sync with appointments missing but 0 appointments in the future. Recurring appointments all gone, but also some incidental ones. Need a fix quick.

Same problem here! Please solve this.

I'm having the same issue and it's really interfering with my planning at work- anyone have a solution?

Good Evening,

 We have Sync errors on all windows PC

On Samsung Galaxy S22ultra Android OK!!

with Exchange Account heinz.bless@cobol.onmicrosoft.com

 Please Help…

Nullable object must have a value. 

System.InvalidOperationException: Nullable object must have a value.

   at System.ThrowHelper.ThrowInvalidOperationException_InvalidOperation_NoValue() + 0x2d

   at System.Nullable`1.get_Value() + 0x12

   at CalendarApp.MicrosoftGraphProvider.CachedMicrosoftAppointment.ExpandAllOccurrences(DateTime, DateTime) + 0x2a7

   at CalendarApp.ProviderBase.CachedAppointment`1.ExpandReccurence(DateTime, DateTime) + 0x1a

   at CalendarApp.ProviderBase.AccountProviderBase`9.UpdateExpandedDataForAppointment(Transaction, TCachedAppointment) + 0x14a

   at CalendarApp.ProviderBase.AccountProviderBase`9.UpdateAppointmentAndExpanded(Transaction, TCachedAppointment) + 0xcc

   at CalendarApp.MicrosoftGraphProvider.MicrosoftGraphAccount.<SyncReceiveCalendarFromProvider>d__7.MoveNext() + 0xb10

--- End of stack trace from previous location where exception was thrown ---

   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x21

   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task) + 0x70

   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task) + 0x38

   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task) + 0x17

   at CalendarApp.MicrosoftGraphProvider.MicrosoftGraphAccount.<SyncReceiveCalendarFromProvider>d__6.MoveNext() + 0x2e2

--- End of stack trace from previous location where exception was thrown ---

   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x21

   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task) + 0x70

   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task) + 0x38

   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task) + 0x17

   at System.Runtime.CompilerServices.TaskAwaiter.GetResult() + 0xb

   at CalendarApp.ProviderBase.AccountProviderBase`9.<SyncReceiveCalendar>d__99.MoveNext() + 0x21b

Same issue on iphone

Same problem. The problem started to occur yesterday. Deleting the account and re-adding it did not help.

Same error. Also, blaming a recurrent appointment as other meetings are showing fine, but all the recurrent ones are missing. I think the error is happening when it starts to sync the recurrent meetings.

I had the exact same issue with my Outlook Calendar.

I noticed that it started happening when I modified a single occurrence of a recurring weekly appointment in my Outlook calendar. After I deleted the single occurrence that I modified, the error disappeared!

Hopefully, this helps the OneCalendar team properly fix the problem.

Same error for me. I rely on OneCalender for my organization. One of the best apps on my android!

I have the same issue

Nullable object must have a value.

Action: ReceiveCalendar
Calendar: Calendar

System.InvalidOperationException: Nullable object must have a value.
at System.Nullable`1[T].get_Value () [0x00008] in <63967f0bb09044ef883acd8c43bb069a>:0
at XCalendarApp.MicrosoftGraphProvider.ProviderTypes.Event.GetTZOriginalStart (XCalendarApp.MicrosoftGraphProvider.ProviderTypes.Event seriesMaster) [0x00110] in <9e1a94b196f243d98bb1369d7cd89ec2>:0
at XCalendarApp.MicrosoftGraphProvider.CachedMicrosoftAppointment.ExpandAllOccurrences (XCalendarApp.Common.Timezones.UtcDateTime rangeStartDate, XCalendarApp.Common.Timezones.UtcDateTime rangeEndDate) [0x000a1] in <9e1a94b196f243d98bb1369d7cd89ec2>:0
at XCalendarApp.ProviderBase.CachedAppointment`1[T].ExpandReccurence (XCalendarApp.Common.Timezones.UtcDateTime rangeStartDate, XCalendarApp.Common.Timezones.UtcDateTime rangeEndDate) [0x00000] in <7145579e108b46fdaa98039821ca82d5>:0
at XCalendarApp.ProviderBase.AccountProviderBase`9[TCachedCalendar,TProviderCalendarItem,TCachedAppointment,TProviderAppointmentItem,TCachedContacts,TCachedContact,TProviderContactItem,TAppointmentDbData,TAccountOptions].UpdateExpandedDataForAppointment (XCalendarApp.SQLite.Transaction trans, TCachedAppointment appointment) [0x00072] in <7145579e108b46fdaa98039821ca82d5>:0
at XCalendarApp.ProviderBase.AccountProviderBase`9[TCachedCalendar,TProviderCalendarItem,TCachedAppointment,TProviderAppointmentItem,TCachedContacts,TCachedContact,TProviderContactItem,TAppointmentDbData,TAccountOptions].UpdateAppointmentAndExpanded (XCalendarApp.SQLite.Transaction trans, TCachedAppointment appointment) [0x0004b] in <7145579e108b46fdaa98039821ca82d5>:0
at XCalendarApp.MicrosoftGraphProvider.MicrosoftGraphAccount.SyncReceiveCalendarFromProvider (XCalendarApp.MicrosoftGraphProvider.CachedMicrosoftCalendar cachedMicrosoftCalendar, XCalendarApp.Model.Data.SyncResults.SyncResult syncResult, XCalendarApp.Common.Timezones.UtcDateTime syncStartDateTime, XCalendarApp.Common.Timezones.UtcDateTime syncEndDateTime, System.String deltaLink) [0x004c8] in <9e1a94b196f243d98bb1369d7cd89ec2>:0
at XCalendarApp.MicrosoftGraphProvider.MicrosoftGraphAccount.SyncReceiveCalendarFromProvider (XCalendarApp.MicrosoftGraphProvider.CachedMicrosoftCalendar cachedMicrosoftCalendar, XCalendarApp.Model.Data.SyncResults.SyncResult syncResult) [0x00236] in <9e1a94b196f243d98bb1369d7cd89ec2>:0
at XCalendarApp.ProviderBase.AccountProviderBase`9[TCachedCalendar,TProviderCalendarItem,TCachedAppointment,TProviderAppointmentItem,TCachedContacts,TCachedContact,TProviderContactItem,TAppointmentDbData,TAccountOptions].SyncReceiveCalendar (TCachedCalendar calendar, XCalendarApp.Model.SyncReason syncReason) [0x0011f] in <7145579e108b46fdaa98039821ca82d5>:0

Hi,
I have the same problem when connecting OneCalendar with M365.
Is there a nice solution for this?

Action: ReceiveCalendar

Calendar: Kalender

System.InvalidOperationException: Nullable object must have a value.

  at System.Nullable`1[T].get_Value () <0x1050d6a74 + 0x00033> in <d51ac11066d245cc85f1489048d5a7ec#91da7f9ae86f59aafcf3e5053c6cf17c>:0

  at XCalendarApp.MicrosoftGraphProvider.ProviderTypes.Event.GetTZOriginalStart (XCalendarApp.MicrosoftGraphProvider.ProviderTypes.Event seriesMaster) <0x10656b300 + 0x00153> in <9e1a94b196f243d98bb1369d7cd89ec2#91da7f9ae86f59aafcf3e5053c6cf17c>:0

  at XCalendarApp.MicrosoftGraphProvider.CachedMicrosoftAppointment.ExpandAllOccurrences (XCalendarApp.Common.Timezones.UtcDateTime rangeStartDate, XCalendarApp.Common.Timezones.UtcDateTime rangeEndDate) <0x10655c86c + 0x003df> in <9e1a94b196f243d98bb1369d7cd89ec2#91da7f9ae86f59aafcf3e5053c6cf17c>:0

  at XCalendarApp.ProviderBase.CachedAppointment`1[T].ExpandReccurence (XCalendarApp.Common.Timezones.UtcDateTime rangeStartDate, XCalendarApp.Common.Timezones.UtcDateTime rangeEndDate) <0x106383c90 + 0x00053> in <7145579e108b46fdaa98039821ca82d5#91da7f9ae86f59aafcf3e5053c6cf17c>:0

  at XCalendarApp.ProviderBase.AccountProviderBase`9[TCachedCalendar,TProviderCalendarItem,TCachedAppointment,TProviderAppointmentItem,TCachedContacts,TCachedContact,TProviderContactItem,TAppointmentDbData,TAccountOptions].UpdateExpandedDataForAppointment (XCalendarApp.SQLite.Transaction trans, TCachedAppointment appointment) <0x10637db50 + 0x00197> in <7145579e108b46fdaa98039821ca82d5#91da7f9ae86f59aafcf3e5053c6cf17c>:0

  at XCalendarApp.ProviderBase.AccountProviderBase`9[TCachedCalendar,TProviderCalendarItem,TCachedAppointment,TProviderAppointmentItem,TCachedContacts,TCachedContact,TProviderContactItem,TAppointmentDbData,TAccountOptions].UpdateAppointmentAndExpanded (XCalendarApp.SQLite.Transaction trans, TCachedAppointment appointment) <0x10637d9d4 + 0x000e3> in <7145579e108b46fdaa98039821ca82d5#91da7f9ae86f59aafcf3e5053c6cf17c>:0

  at XCalendarApp.MicrosoftGraphProvider.MicrosoftGraphAccount.SyncReceiveCalendarFromProvider (XCalendarApp.MicrosoftGraphProvider.CachedMicrosoftCalendar cachedMicrosoftCalendar, XCalendarApp.Model.Data.SyncResults.SyncResult syncResult, XCalendarApp.Common.Timezones.UtcDateTime syncStartDateTime, XCalendarApp.Common.Timezones.UtcDateTime syncEndDateTime, System.String deltaLink) <0x106550820 + 0x0141b> in <9e1a94b196f243d98bb1369d7cd89ec2#91da7f9ae86f59aafcf3e5053c6cf17c>:0

  at XCalendarApp.MicrosoftGraphProvider.MicrosoftGraphAccount.SyncReceiveCalendarFromProvider (XCalendarApp.MicrosoftGraphProvider.CachedMicrosoftCalendar cachedMicrosoftCalendar, XCalendarApp.Model.Data.SyncResults.SyncResult syncResult) <0x10654fe60 + 0x007af> in <9e1a94b196f243d98bb1369d7cd89ec2#91da7f9ae86f59aafcf3e5053c6cf17c>:0

  at XCalendarApp.ProviderBase.AccountProviderBase`9[TCachedCalendar,TProviderCalendarItem,TCachedAppointment,TProviderAppointmentItem,TCachedContacts,TCachedContact,TProviderContactItem,TAppointmentDbData,TAccountOptions].SyncReceiveCalendar (TCachedCalendar calendar, XCalendarApp.Model.SyncReason syncReason) <0x106329bc0 + 0x00477> in <7145579e108b46fdaa98039821ca82d5#91da7f9ae86f59aafcf3e5053c6cf17c>:0

I have the same issue. Google and Outlook calendars set up, but only the Google one works:

Nullable object must have a value.

System.InvalidOperationException: Nullable object must have a value.
at System.ThrowHelper.ThrowInvalidOperationException_InvalidOperation_NoValue() + 0x2d
at System.Nullable`1.get_Value() + 0x12
at CalendarApp.MicrosoftGraphProvider.CachedMicrosoftAppointment.GetModifiedOccurrences() + 0x147
at CalendarApp.ProviderBase.CachedAppointment`1.SetRecurrenceEndDate() + 0xe5
at CalendarApp.ProviderBase.CachedAppointment`1.get_CurrentFieldValues() + 0x3c
at CalendarApp.ProviderBase.CachedAppointment`1.SetRecurrenceEndDate() + 0x3a
at CalendarApp.MicrosoftGraphProvider.CachedMicrosoftAppointment.AddOccurrence(Event) + 0x126
at CalendarApp.MicrosoftGraphProvider.MicrosoftGraphAccount.<SyncReceiveCalendarFromProvider>d__7.MoveNext() + 0xad6
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x21
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task) + 0x70
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task) + 0x38
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task) + 0x17
at CalendarApp.MicrosoftGraphProvider.MicrosoftGraphAccount.<SyncReceiveCalendarFromProvider>d__6.MoveNext() + 0x2e2
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x21
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task) + 0x70
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task) + 0x38
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task) + 0x17
at System.Runtime.CompilerServices.TaskAwaiter.GetResult() + 0xb
at CalendarApp.ProviderBase.AccountProviderBase`9.<SyncReceiveCalendar>d__99.MoveNext() + 0x21b