SQL Server Reporting Studio report showing "ERROR#" or invalid data type error

Question

I struggled with this issue for too long before finally tracking down how to avoid/fix it. It seems like something that should be on StackOverflow for the benefit of others.

I had an SSRS report where the query worked fine and displayed the string results I expected. However, when I tried to add that field to the report, it kept showing "ERROR#". I was eventually able to find a little bit more info:

The Value expression used in [textbox] returned a data type that is not valid.

But, I knew my data was valid.

Solution 1

Found the answer here.

Basically, it's a problem with caching and you need to delete the ".data" file that is created in the same directory as your report. Some also suggested copying the query/report to a new report, but that appears to be the hard way to achieve the same thing. I deleted the .data file for the report I was having trouble with and it immediately started working as-expected.

Solution 2

After you preview the report, click the refresh button on the report and it will pull the data again creating an updated rdl.data file.

Solution 3

Another solution to this issue is to click Refresh Fields in the Dataset Properties menu.

This will update the list of fields, and force SSRS to get new data, rather than relying on a cached version.

Comments

[wruckie]

mark your answer as the answer

[Josh]

I have to wait 2 days.

[Bengie]

I changed a parameter, which invalidates the cache. It worked for me.

[Zach Wymer]

This does not work. I clicked "Refresh Fields" and changed the name of the returning column. No dice. Deleting .data is the way.

[YtramX]

Thank you so much! This was driving me insane!

[Mathews Sunny]

This is just of comment quality

[JosephDoggie]

Sometimes also closing / re-opening VS studio is required as well.

[phn]

Just to be clear - you need to delete the .rdl.data file that belongs to the report. I spent some time looking for a file called .data before I worked it out.After that it works - thanks!

[Benzo]

I want to know why the visual studio "clean" function doesn't remove these cached files, Like I would expect a "clean" process to do.

[jw11432]

Makes absolute sense. I was actually wondering how my query, which took some time to load, could so instantly spit out results in my report each time. The caching as it pertains to the .rdl.data file completes the picture in my head. Fantastic and valuable information, thank you!