Null Reference Exception while opening a docx file

[ManuelHaas]

What happened:
When trying to view a specific docx file a NullReferenceException occurs.
I cannot upload the docx file here but I can provide the file if necessary.

2026-04-08 16:20:07.317 +02:00 [ERR] Failed to read document description.
System.NullReferenceException: Object reference not set to an instance of an object.
at gUZ.B()
at EUJ.d(Boolean d, Boolean v)
at EUJ.d(Boolean d)
at JUJ.d(EUJ d)
at JUJ.d(oUJ d, Int32 v)
at xUJ.c(oUJ d)
at xUJ.d(oUJ d)
at SUJ.d(oUJ d, Boolean& v)
at SUJ.v(oUJ d, Int32 v, Boolean c)
at SUJ.d(oUJ d, Int32 v, Boolean c)
at cU5.v()
at cU5.v(vU5 d, Int32 v, Boolean c)
at yUQ.v()
at yUQ.v(pUZ d, Int32 v, Boolean c, Boolean t)
at yUQ.d(pUZ d, Int32 v, Boolean c, Boolean t)
at hU5.d(yUQ d)
at hU5.d()
at oU5.d.JU5iFd(FUZ d)
at CUZ.d(FUZ d)
at oU5.v(hU5 d)
at oU5.v(kUq d)
at SUq.JU5iFd(FUZ d)
at CUZ.d(FUZ d)
at OU5.d(kUq d)
at mU5.O()
at hU0.c()
at Aspose.Words.Document.UpdatePageLayout()
at OUc.OUciFd()
at bUc.d(FUW d)
at pUW.d(FUW d, FUW v)
at pUW.d(pUW d)
at pUW.d(Node d, pUW v)
at pUW.d(Node d)
at Aspose.Words.Range.UpdateFields()
at Aspose.Words.Document.UpdateFields()
at ���.�(Boolean �)
at ���.������(BaseViewOptions �)
at ���.������(String �, Stream �, LoadOptions �, BaseViewOptions �, CancellationToken �)
at GroupDocs.Viewer.Viewer.�(LoadOptions �, BaseViewOptions �, CancellationToken �)
at GroupDocs.Viewer.Viewer.�(BaseViewOptions �, CancellationToken �)
at GroupDocs.Viewer.Viewer.�(ViewInfoOptions �, CancellationToken �)
at GroupDocs.Viewer.Viewer.GetViewInfo(ViewInfoOptions options)
at GroupDocs.Viewer.UI.SelfHost.Api.Viewers.BaseViewer.GetDocumentInfoAsync(FileCredentials fileCredentials)
at GroupDocs.Viewer.UI.SelfHost.Api.Viewers.BaseViewer.GetDocumentInfoAsync(FileCredentials fileCredentials)
at GroupDocs.Viewer.UI.Core.FileCacheExtensions.GetValueAsync[TEntry](IFileCache cache, String cacheKey, String filePath, Func`1 acquire)
at GroupDocs.Viewer.UI.Core.Caching.CachingViewer.GetDocumentInfoAsync(FileCredentials fileCredentials)
at GroupDocs.Viewer.UI.Api.Controllers.ViewerController.ViewData(ViewDataRequest request)

Environment:

• .NET Core version 10.0.5
• GroupDocs.Viewer.UI version 8.1.5

[vladimir-litvinchik]

Hi, @ManuelHaas!

Thank you for reporting this issue. You can send the file to developers@groupdocs.com mail box so we could check the issue.

Thanks

[denis-gvardionov]

Hi @ManuelHaas

We successfully reproduced the exception on our side, it is considered as a bug. We logged it in our internal tracking system as "VIEWERNET-5651" and our developers will take a look on it shortly.

[ManuelHaas]

@denis-gvardionov thanks for the update!
In the meantime, can you tell me what I need to change in the docx document so that it can be displayed in the viewer?

[denis-gvardionov]

@ManuelHaas

Unfortunately, at this moment I cannot answer this question. We reproduced the exception, logged and transfered to the responsible dev team. For now we still have no any feedback regarding this issue.