Forum Discussion
Purview on-demand classification "cost-estimation" still in progress!
hi everyone,
I've initiated a Microsoft Purview on-demand classification cost estimation, which has been running for almost two weeks without any visible progress information.
Scan configuration:
- Workloads: SharePoint Online and OneDrive for Business
- Scope: Files created within the past 7 years
- File types: PDF and Microsoft Office documents only
- Total repository inventory: Over 250 million files
- Documented Purview limit: 100 million files per scan
The Purview portal continues to display Estimation in progress, but provides no progress percentage, estimated file count, or other useful metrics.
I've also tried several PowerShell commands, including Get-SensitiveInformationScan -IncludeImpactAssessment $true, but haven't been able to retrieve meaningful progress information.
The PowerShell output currently shows:
SensitiveInformationScanStatus : ImpactAssessmentInvalid | LastImpactAssessmentStartTime : 23/10/2026 | LastImpactAssessmentCompletionTime : [Empty] | LastStatusUpdateTime : [Empty] | IsEstimationStopped : False | ErrorMetadata : [Empty]
My questions are:
- How can I verify whether the estimation job is actively processing files, queued, stalled, or silently failed? Are there any additional PowerShell cmdlets, diagnostic logs, or metrics available?
- Does the 100-million-file limit apply to the entire repository inventory or only to files matching the configured date and file-extension filters? For example, if the repository contains 250 million files but only 80 million meet the scan scope, would the scan remain within the supported limit?
- Is on-demand classification subject to daily processing or throttling limits, similar to the 100,000-items-per-day limit associated with certain auto-labelling scenarios? If so, what are the documented limits for cost estimation versus actual classification?
- What does ImpactAssessmentInvalid indicate? Is this an expected intermediate status during estimation, or does it suggest an issue requiring Microsoft Support intervention?
I'm particularly interested in experiences from organisations that have run Purview on-demand classification across very large SharePoint and OneDrive environments.
Any insights, Microsoft documentation, or practical troubleshooting recommendations would be appreciated.
3 Replies
Update: the scan failed after 12 days so I deleted the scan job then created 2 separate scan job - one for SharePoint (scoped to 34 sites) and one for OneDrive (scoped to 33 accounts). This time though the scan finished within 24 hours and discovered around 3 million files on SPO and 1.3 million files on ODB. However, the dashboard shows 194 sites and 122 accounts were scanned while the exported excel report shows the correct scope (34 and 33). Not sure why the report dashboard has such discrepancy.
The useful distinction here is between the scan’s supported scope and evidence that your particular estimation is progressing. Microsoft documents the 100-million-file and 150,000-location limits as enforced from scan estimation results. An estimated 80 million matching files would be below the file cap; the tenant’s total inventory alone is not that estimate. Check the configured last-modified date range, rather than assuming it means creation date.
For estimation, IncludeImpactAssessment refreshes status; IncludeScanProgress refreshes classification status. IncludeProgressForAllActiveScans is reserved for Microsoft’s internal use. Check View estimation > Estimation overview for progress and items found.
The documentation does not define ImpactAssessmentInvalid or establish a SharePoint/OneDrive daily throughput guarantee. Do not import auto-labelling limits. Given your empty timestamps, preserve the scan ID and outputs and request Microsoft support to inspect the backend state before cancelling. Those fields cannot confirm active processing.
With ImpactAssessmentInvalid, no completion timestamp and almost two weeks without progress, I’d open a Microsoft support case now rather than assume the estimate is still processing.
The fields shown don’t establish that the job is active: IsEstimationStopped : False only says it isn’t marked stopped, and empty ErrorMetadata doesn’t prove success. I wouldn’t interpret ImpactAssessmentInvalid as a normal intermediate state without confirmation from Microsoft.
For the scale questions, keep these distinctions separate:
- 250 million total files versus 80 million matching files: don’t assume the filters make the job compliant with the 100-million limit. The important question is whether that limit applies before or after filtering, and whether estimation has its own enumeration constraints. Ask support to confirm this for your configuration.
- Estimation versus classification: don’t apply an auto-labelling daily limit to this workflow unless Microsoft explicitly documents it. These are different operations.
Provide the scan identifier, full configuration, PowerShell output, UTC start time and portal screenshots. Ask support to check the backend job state, last successful processing activity, and whether the scope was rejected or exceeded a service limit.
Preserve those details before cancelling or recreating the job. A smaller, non-overlapping site scope could be a useful diagnostic test, but wouldn’t explain or repair the original job by itself.
