What are System Files?

The System File format is used to store critical computer data to be used by an operating system. Some examples include device drivers, system libraries, and other critical configuration details. Important to the functioning of the operating system, companies like Microsoft also implement certain precautions like applying a system attribute to prevent accidental deletion of such files.

Popular System File Extensions

PPD — Format: Unknown
Developed by Adobe Systems, the “PPD” or PostScript Printer Description file format is used to store settings details like the font, paper size, memory configuration and some other information for a PostScript printer. It also stores other data and code necessary for the printer to function like the PostScript code required to invoke features for the print job.
XRM-MS — Format: Unknown
Developed by Microsoft, the XRM-MS file format acts as the Microsoft Security Certificate file and is used to store certificate data. It also contains an additional software to digitally verify that the purchase of a software is valid.
ADML — Format: Text
Developed by Microsoft, the ADML file format is used by the Group Policy Object Editor, a Windows software to manage group permissions for a set of computers. It stores details about the settings for the program.
ADMX — Format: Binary
Developed by Microsoft, the ADMX file format is used by the Group Policy Object Editor, a Windows software to manage group permissions for a set of computers. A settings file, it is stored in the XML format and it specifies which registry keys in the Windows Registry are changed if a Group Policy setting is changed.
CUR — Format: Binary
CUR or the Windows Cursor File format is used to store a static or animated cursor image. They are almost the same as .ICO (or icon) files.

Top System File Extensions

File Extension	Total Number of Files	Oldest File (Date)	Latest File (Date)
MAPIMAIL	1	Mail Recipient.MAPIMail (09/18/2006)	Mail Recipient.MAPIMail (03/04/2020)
NLD	3	wbdbase.nld (04/14/2008)	wbdbase.nld (04/14/2008)
DYC	38	XBA55P_A.DYC (09/18/2006)	XWA75L_A.DYC (09/18/2006)
PROFILE	9	WWAHost_AppexSports.profile (07/26/2012)	CSharp.Profile (12/02/2019)
NT	2	autoexec.nt (04/14/2008)	config.nt (04/24/2017)
BR2	1	M1033Eva.BR2 (03/18/2017)	M1033Eva.BR2 (03/18/2017)
DBL	1	wpa.dbl (04/24/2017)	wpa.dbl (08/29/2019)
TASKS	1	Microsoft.Common.Tasks (01/21/2008)	Microsoft.Common.Tasks (10/05/2019)
ADML	215	WindowsMediaDRM.adml (11/02/2006)	OneDrive.adml (03/30/2020)
MYDOCS	2	My Documents.mydocs (04/24/2017)	Documents.mydocs (04/24/2017)
CUR	436	size1_rm.cur (09/18/2006)	AddStickerNote.cur (02/11/2020)
UCE	8	SubRange.uce (11/02/2006)	SubRange.uce (03/18/2017)
GMMP	4	Graphics.gmmp (09/18/2006)	Photo.gmmp (03/18/2017)
ANI	113	drum.ani (11/02/2006)	pdf2html.ani (02/12/2020)
XRM-MS	2156	MicrosoftWindowsSafeDocsMain-ppdlic.xrm-ms (01/21/2008)	osppobjs-spp-plugin-manifest-signed.xrm-ms (03/04/2020)
OVERRIDETASKS	1	Microsoft.Common.OverrideTasks (06/02/2012)	Microsoft.Common.OverrideTasks (03/18/2017)
ADMX	217	WindowsMediaDRM.admx (11/02/2006)	OneDrive.admx (03/30/2020)
EBD	3	systemsf.ebd (04/11/2009)	ResPriStaticDb.ebd (04/24/2017)
IDX	40	M1033DSK.IDX (09/18/2006)	psanbla.idx (03/05/2020)
CNT	72	CNBJHLP2.CNT (09/18/2006)	speech.cnt (03/05/2020)
ADM	24	inetcorp.adm (04/14/2008)	AER_1033.ADM (01/29/2020)
CHS	2	NOISE.CHS (09/18/2006)	extension.chs (01/02/2020)
JPN	2	noise.jpn (09/18/2006)	SmartVCD.Jpn (11/25/2019)
HTT	13	PUBPLACE.HTT (04/24/2003)	eTransmit.htt (01/20/2020)
SEARCHCONNECTOR-MS	12	connectedsearch-music.searchconnector-ms (06/18/2013)	Microsoft Office Outlook.searchconnector-ms (02/15/2020)
LIBRARY-MS	7	RecordedTV.library-ms (07/14/2009)	Pictures.library-ms (11/23/2019)
GRL	2	Pending.GRL (11/02/2006)	Pending.GRL (03/18/2017)
WPRP	1	provtrace.wprp (03/18/2017)	provtrace.wprp (03/18/2017)
IEM	2	inetset.iem (11/02/2006)	inetset.iem (04/12/2011)
ITS	6	MSB1ENES.ITS (05/10/2017)	MSB1FREN.ITS (03/04/2020)
SETTINGCONTENT-MS	456	AAA_SystemSettings_Users_AssignedAccess.settingcontent-ms (07/24/2013)	NameSpace_Classic_0_FlashPlayerCPLApp.cpl.settingcontent-ms (04/24/2017)
VXD	13	dsound.vxd (04/14/2008)	ndphlpr.vxd (02/21/2020)
ESN	3	wbdbase.esn (04/14/2008)	wbdbase.esn (04/14/2008)
EFTX	53	Verve.eftx (05/10/2017)	Verve.eftx (03/04/2020)
GID	14	vba_acc.GID (05/10/2017)	Wspelldlg.GID (01/10/2020)
PPD	1568	BRH24CE3.PPD (09/18/2006)	MSXPSINC.PPD (03/04/2020)
CLB	7	R000000000001.clb (09/18/2006)	R000000000004.clb (02/21/2020)
EVTX	192	Microsoft-Windows-Kernel-StoreMgr%4Operational.evtx (04/24/2017)	Microsoft-Windows-Windows Defender%4Operational.evtx (03/30/2020)
FTG	1	VBAACCSP.FTG (05/10/2017)	VBAACCSP.FTG (05/10/2017)
CDMP	2	wsRGB.cdmp (09/18/2006)	wsRGB.cdmp (03/18/2017)
AUTOMATICDESTINATIONS-MS	4	f01b4d95cf55d32a.automaticDestinations-ms (04/24/2017)	5f7b5f1e01b83767.automaticDestinations-ms (04/24/2017)
DESKLINK	1	Desktop (create shortcut).DeskLink (09/18/2006)	Desktop (create shortcut).DeskLink (03/04/2020)
DIAGPKG	1	DiagPackage.diagpkg (07/13/2009)	DiagPackage.diagpkg (03/18/2017)
FTS	6	VBAACCSP.FTS (05/10/2017)	MSGRAPH.FTS (05/10/2017)
CUSTOMDESTINATIONS-MS	4	7e4dca80246863e3.customDestinations-ms (04/24/2017)	7e4dca80246863e3.customDestinations-ms (04/24/2017)
CI	15	00010001.ci (04/24/2017)	extension.ci (01/02/2020)
ITEMDATA-MS	1	appsFolder.itemdata-ms (04/24/2017)	appsFolder.itemdata-ms (05/10/2017)
HHK	19	scoped_5.hhk (04/24/2017)	Index.hhk (11/28/2019)
BLF	1	KtmRmTm.blf (04/24/2017)	KtmRmTm.blf (05/10/2017)
THEME	42	Windows Classic.theme (09/18/2006)	index.theme (01/13/2020)
CWL	1	SAMPLE1.CWL (05/10/2017)	SAMPLE1.CWL (05/10/2017)
PROPDESC	10	ie8props.propdesc (11/21/2010)	VisioCustom.propdesc (03/04/2020)

What are System Files?

Popular System File Extensions

File Database Breakdown - System File Extensions

Top System File Extensions