We recently learned the hard way that there is a limit to how many sheets a report can access! We use the report feature to create individual task lists throughout our company. Each task list searches all sheets for names in an Assigned To column and refines the search looking for a value of "Needs Action" in the Status column. Those reports stopped working last Monday and SmartSheet still has not found a resolution.
Use caution when planning to use the Report function for your implementation of SmartSheet within your company.
Note from tech support: "we are experiencing a Smartsheet based issue when trying to load Reports that are pulling from a large number of sheets"