Hi,

I randomly get an error in edit mode for a LinkItemCollection in my solution that is running CMS 7.

When clicking on the edit button for a LinkItemCollection the following error is shown in the modal:

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Detailed error information (authorized by permissions to functions)
Error occured 06.02.2019 11:06:40
User IP ....
User Agent ...
Url https://...../../CMS/edit/EditProperty.aspx?moduleArea=LegacyCMS&epslanguage=null&propertyname=LinkList.Links&id=215_24671
Referer https://..../.../Cms/

Value cannot be null.
Parameter name: str

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: str

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[ArgumentNullException: Value cannot be null.
Parameter name: str]
System.String.Copy(String str) +14342734
EPiServer.SpecializedProperties.LinkItem.Clone() +355
EPiServer.SpecializedProperties.LinkItemCollection.Clone() +250
EPiServer.SpecializedProperties.PropertyLinkCollection.CreateWritableClone() +191
EPiServer.Core.PropertyDataCollection.CreateWritableClone() +125
EPiServer.Core.ContentData.CreateWriteableCloneImplementation() +102
Castle.Proxies.Invocations.ContentData_CreateWriteableCloneImplementation_2.InvokeMethodOnTarget() +37
Castle.DynamicProxy.AbstractInvocation.Proceed() +116
EPiServer.DataAbstraction.RuntimeModel.ContentDataInterceptor.Intercept(IInvocation invocation) +376
Castle.DynamicProxy.AbstractInvocation.Proceed() +595
Castle.Proxies.LinkListBlockProxy.CreateWriteableCloneImplementation() +154
EPiServer.Core.BlockData.CreateWritableClone() +14
Castle.Proxies.Invocations.BlockData_CreateWritableClone_2.InvokeMethodOnTarget() +37
Castle.DynamicProxy.AbstractInvocation.Proceed() +116
EPiServer.DataAbstraction.RuntimeModel.ContentDataInterceptor.Intercept(IInvocation invocation) +376
Castle.DynamicProxy.AbstractInvocation.Proceed() +595
Castle.Proxies.LinkListBlockProxy.CreateWritableClone() +154
EPiServer.SpecializedProperties.PropertyBlock`1.CreateWritableClone() +160
EPiServer.Core.PropertyDataCollection.CreateWritableClone() +125
EPiServer.Core.PageData.CreateWriteableCloneImplementation() +102
Castle.Proxies.Invocations.PageData_CreateWriteableCloneImplementation_1.InvokeMethodOnTarget() +40
Castle.DynamicProxy.AbstractInvocation.Proceed() +116
EPiServer.DataAbstraction.RuntimeModel.ContentDataInterceptor.Intercept(IInvocation invocation) +376
Castle.DynamicProxy.AbstractInvocation.Proceed() +595
Castle.Proxies.ArticlePageProxy.CreateWriteableCloneImplementation() +157
EPiServer.UI.Edit.EditProperty.Page_Init(Object sender, EventArgs e) +137
System.Web.UI.Page.OnInit(EventArgs e) +102
EPiServer.UI.ContentBaseWebForm.OnInit(EventArgs e) +16
System.Web.UI.Control.InitRecursive(Control namingContainer) +186
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2098

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For me it seems that this is related to Episerver and not our implementation. Does anyone have an idea about what can be the reason?

Thank you in advance.

Cathinka