Custom Content Type - File Formats - XLSB supported?

Occasional Contributor



I recently set up custom content types for my standard templates so that everybody (in subsites) can benefit from it using the NEW button.

So far so good, all documents open, I only have 2 issues:


1) XLSB Files open Excel but with a popup message stating:
"The file format and extension of "<documentname>.htm" don't match. The file could be corrupted or unsafe. Unless you trust its source, don't open it. Do you want to open it anyway?
Don't know why it says this is a HTM file when I clearly reference an XLSB file...


2) a minor issue, but annoying nontheless. PPTX files are not created with the Document Title in mind, they are always loaded as "Presentation1". Can they be made to obey and read the title properly?

Fun fact, both XLSX and XLSB obey the title...




4 Replies
I'm afraid there is not a way to solve both issues:
1) I think the New button is expecting a xlsx, pptx, doccx extension type so as soon as you try another when it starts "complaining" with weird messages
2) No way to instruct Content Type configuration to read the title property for PPTX files

After opening a Ticket with Microsoft regarding XLSB, I have the following news:

- XLSB files do seem to open fine now (don't know how the error message vanished...)

- XLSB files, when opened and then saved are switched to XLSM (which is uncomfortable, especially if I want to all users to use XLSB by default (update pending on this one still).


Another update:

The Error Message is back for XLSB.

Opening the Document from the Document library works fine, but opening it as a Template document via the NEW button will result in Excel wanting to open the document as a HTM file.

No changes to the Trust Center, IE trusted Sites settings or Excel Save options have yielded a different behaviour.

At this point I am fairly certain that the Bug lies with SharePoint adding something at the End of the Document which breaks Excels identification of the File Type (and proper handling thereof)


The file I specified in the Custom Site Content was "/VT/Templates/XLSB.xlsb"

It is briefly visible in the Splash Screen of Excel that something is attached to the end (but cut off):


I do not know what it is, but it is messing with the file type.



XLSB-behaviour is apparently unintended (as we have encountered a few issues) and with the team to resolve.


PPTX title is as yet unclear whether it is intended behaviour or also a bug. (I personally think it is the latter, since no Document Metadata is taken into account for PPTX)