What is the CVR file format?
.cvr files are created automatically by Microsoft Office applications when an error occurs or the application crashes. They are part of the Windows Error Reporting (WER) pipeline - also known as Microsoft Watson - which collects diagnostic data for transmission to Microsoft.
What do .cvr files contain?
.cvr files usually contain detailed data regarding device configuration settings, information about the operating system and installed drivers, as well as the operation that caused the error. Collected information is used for error troubleshooting; analysis is conducted by Microsoft engineers based on the report generated by the Windows crash reporter and saved in the .cvr file. The file is a binary payload with no documented public format and cannot be opened by a standard viewer.
Can I delete .cvr files?
.cvr files are saved in the Temp system directory, typically at the path stored in %LOCALAPPDATA%\Temp or %TEMP%. On an error-prone or poorly maintained system, accumulated .cvr report files can take up a dozen or more gigabytes of disk space. Fortunately, .cvr files can be safely removed using the built-in Windows Disk Cleanup tool or by manually clearing the Temp folder - they contain no user documents or recoverable work.
Modern Windows crash telemetry has largely moved to .wer and .mdmp files. Note that .cvr is also used by unrelated programs such as WinFax (fax cover pages) and CorelCAD - those are entirely different formats that share only the extension name.
Security & safety
RISK: LOWAn Office .cvr crash report is a passive diagnostic file, not executable, so it poses no direct risk and can be deleted safely. It may contain small fragments of process state, so as minor privacy hygiene avoid emailing it around, but it is not your document. Be wary only of online "CVR viewer/opener" download portals - there is no real viewer for this internal format, so such sites are typically adware/PUP traps. If Office crashes repeatedly, repair Office rather than hunting for a viewer.
Format details
in a nutshell- WinFax / fax cover page - Some fax programs (e.g. WinFax) use .cvr for a fax cover-page sheet - a different format from the Office crash report.
- CorelCAD / Corel custom view - CorelCAD and some Corel tools have used .cvr for saved custom views/settings - unrelated to either of the above.
Programs that open CVR files
Windows2 apps
(No viewer needed - safe to delete)
Built-in Not a document: there is nothing to open. Delete from %LOCALAPPDATA%\Temp, or run Disk Cleanup. To recover lost work use Office AutoRecover, not the .cvr.
Microsoft Office (repair)
Paid If Office keeps crashing and creating .cvr files, run Online Repair (Settings > Apps > Microsoft 365 > Modify > Online Repair) to stop the crashes at the source. Technical details
deep spec| Developer | Microsoft |
| Encoding | Binary (little-endian) |
| MIME type | application/octet-stream |
| Container | Windows Error Reporting (WER) / Microsoft Watson crash payload |
| Associated OS | Windows |
| Typical size | A few KB to tens of KB |
| Default location | %LOCALAPPDATA%\Temp or the path referenced by %TEMP% |
| Related extensions | .wer, .dmp, .mdmp, .tmp |
| Safe to delete | Yes - contains no user documents or recoverable work |
| Superseded by | .wer and .mdmp telemetry in modern Windows Error Reporting |
| Also known as | Office crash dump; Watson crash report (Office) |
| Magic bytes | No documented public signature - undocumented internal binary format |
| User-openable | No - internal diagnostic file; no standard viewer exists |
| Generated by | Microsoft Office applications on crash or unhandled exception |
| Released | Office XP / Office 2003 era (Microsoft Watson / Windows Error Reporting) |
| Latest version | N/A (internal diagnostic file; no public versioned spec) |
Community Q&A
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