Error when saving with Excel on OneDrive as data source.

[shentz]

I have a very simply app which has an Excel file as data source. There are five fields on the app (one date and four text fields). I built the app using the online wizard, which linked to a simple table in a spreadsheet on OneDrive as data source.

The app works okay for a while, and I can add/edit new records using either the online app, the app in Teams or on a mobile.

However, after a few uses the following error starts appearing:

Error in implicit conversion. Cannot convert null object (I have attached an image of this error).

This error prevents the adding of new records, or the amending of existing ones. Even if I open an existing record and click save, I get the error - with no change to the underlying data.

None of the fields contains null values. The spreadsheet appears fine. It is not locked. All the fields are populated in the spreadsheet for existing records. I can view all records on the app. I therefore cannot understand the reference to null.

I have not been able to find a single reference to this specific error online and I was hoping this forum would be a good starting point for anyone with ideas about how to fix it.

Thanks

[jlindstrom · Accepted solution]

So the error is failed to read. Is more than one person using the app, or is the excel file open somewhere? If you added the app in teams it is likely open by more than one person. If it is, the app will fail with that kind of error because the excel file is locked. Excel based apps can only be used by one person at a time. Go to another data source like sharepoint if you need more than a single user. I’ve even locked an excep

based app by myself by having the app open in two places at the same time

[shentz]

Thank you for your reply. There is just one user using the spreadsheet and it is not open elsewhere. I will migrate over to SharePoint, though, as per your suggestion because it offers a much more robust way of providing a data source. And it will allow for multiple user access if and when required in the future.