diff --git a/public/filesystem.h b/public/filesystem.h
index aa14351c..95fdc7fc 100644
--- a/public/filesystem.h
+++ b/public/filesystem.h
@@ -747,7 +747,7 @@ public:
 	// As the server loads whitelists when it transitions maps, it calls this to calculate CRCs for any files marked
 	// with check_crc.   Then it calls CheckCachedFileCRC later when it gets client requests to verify CRCs.
 	virtual void			CacheFileCRCs( const char *pPathname, ECacheCRCType eType, IFileList *pFilter ) = 0;
-	virtual EFileCRCStatus	CheckCachedFileHash( const char *pPathID, const char *pRelativeFilename, FileHash_t *pFileHash ) = 0;
+	virtual EFileCRCStatus	CheckCachedFileHash( const char *pPathID, const char *pRelativeFilename, int nFileFraction, FileHash_t *pFileHash ) = 0;
 	
 	// Fills in the list of files that have been loaded off disk and have not been verified.
 	// Returns the number of files filled in (between 0 and nMaxFiles).
diff --git a/public/filesystem_passthru.h b/public/filesystem_passthru.h
index a89623dd..5453fe29 100644
--- a/public/filesystem_passthru.h
+++ b/public/filesystem_passthru.h
@@ -223,8 +223,8 @@ public:
 		{ m_pFileSystemPassThru->MarkAllCRCsUnverified(); }
 	virtual void CacheFileCRCs( const char *pPathname, ECacheCRCType eType, IFileList *pFilter )
 		{ return m_pFileSystemPassThru->CacheFileCRCs( pPathname, eType, pFilter ); }
-	virtual EFileCRCStatus CheckCachedFileHash( const char *pPathID, const char *pRelativeFilename, FileHash_t *pFileHash )
-		{ return m_pFileSystemPassThru->CheckCachedFileHash( pPathID, pRelativeFilename, pFileHash ); }
+	virtual EFileCRCStatus CheckCachedFileHash( const char *pPathID, const char *pRelativeFilename, int nFileFraction, FileHash_t *pFileHash )
+		{ return m_pFileSystemPassThru->CheckCachedFileHash( pPathID, pRelativeFilename, nFileFraction, pFileHash ); }
 	virtual int GetUnverifiedFileHashes( CUnverifiedFileHash *pFiles, int nMaxFiles )
 		{ return m_pFileSystemPassThru->GetUnverifiedFileHashes( pFiles, nMaxFiles ); }
 	virtual int GetWhitelistSpewFlags()