Based on your description, I wouldn't immediately conclude it's a Microsoft service issue. The error:
> DataFormat.Error: We couldn't convert to Number. Microsoft.Data.Mashup.ErrorCode = 10041
typically indicates that Power Query is encountering a value that cannot be converted to a numeric type during the actual refresh, even if the query previews load successfully.
A few things I'd recommend checking:
1. Refresh Preview vs. Full Refresh
The Power Query preview only loads a subset of the data, whereas a full refresh processes the entire dataset. It's possible the problematic value exists outside the preview sample.
2. Review "Changed Type" steps
Check each query for automatic Changed Type steps. If a column expected to be numeric now contains text, blanks, commas, or unexpected characters, the full refresh can fail.
3. Disable parallel loading temporarily
In Power BI Desktop, go to File > Options and settings > Options > Data Load and temporarily disable parallel loading. This can sometimes make it easier to identify which query is failing.
4. Enable Query Diagnostics
Use Tools > Query Diagnostics in Power BI Desktop to determine which query and step is failing during the refresh.
5. Review the data source
If the source files are generated automatically, verify whether any recent changes introduced values such as commas, currency symbols, spaces, or empty strings into columns expected to contain numbers.
6. Try isolating the failing query
Disable the load for all queries except one and refresh incrementally until you identify which query is causing the error.
Since you mentioned that the error message no longer identifies the file, that could indicate a recent change in error reporting, but the underlying issue is still likely a data conversion problem rather than a platform-wide outage.
A couple of questions that would help narrow it down:
What is your data source (Excel, CSV, SharePoint, SQL, etc.)?
Did the issue start after updating Power BI Desktop or after changing the source data?
Does the failure occur both in Power BI Desktop and in the Power BI Service, or only in one of them?
If multiple users are experiencing the exact same behavior after a recent update, it may be worth checking the Power BI Service Health dashboard or the Fabric/Power BI community to see if a regression has been reported.
