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)
NLD	3	noise.nld (04/14/2008)	noise.nld (04/14/2008)
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)
FTG	1	VBAACCSP.FTG (05/10/2017)	VBAACCSP.FTG (05/10/2017)
HTT	13	PUBPLACE.HTT (04/24/2003)	eTransmit.htt (01/20/2020)
CUSTOMDESTINATIONS-MS	4	7e4dca80246863e3.customDestinations-ms (04/24/2017)	7e4dca80246863e3.customDestinations-ms (04/24/2017)
LIBRARY-MS	7	RecordedTV.library-ms (07/14/2009)	CameraRoll.library-ms (11/23/2019)
OVERRIDETASKS	1	Microsoft.Common.OverrideTasks (06/02/2012)	Microsoft.Common.OverrideTasks (03/18/2017)
PROFILE	9	WWAHost_AppexSports.profile (07/26/2012)	CSharp.Profile (12/02/2019)
ADMX	217	WindowsMediaDRM.admx (11/02/2006)	OneDrive.admx (03/30/2020)
NT	2	autoexec.nt (04/14/2008)	config.nt (04/24/2017)
ITEMDATA-MS	1	appsFolder.itemdata-ms (04/24/2017)	appsFolder.itemdata-ms (05/10/2017)
IEM	2	inetset.iem (11/02/2006)	inetset.iem (04/12/2011)
CUR	436	arrow_r.cur (09/18/2006)	AddStickerNote.cur (02/11/2020)
CDMP	2	wsRGB.cdmp (09/18/2006)	wsRGB.cdmp (03/18/2017)
CWL	1	SAMPLE1.CWL (05/10/2017)	SAMPLE1.CWL (05/10/2017)
CNT	72	CNBJHLP2.CNT (09/18/2006)	speech.cnt (03/05/2020)
XRM-MS	2156	MicrosoftWindowsSafeDocsMain-ppdlic.xrm-ms (01/21/2008)	osppobjs-spp-plugin-manifest-signed.xrm-ms (03/04/2020)
PROPDESC	10	ie8props.propdesc (11/21/2010)	VisioCustom.propdesc (03/04/2020)
JPN	2	noise.jpn (09/18/2006)	SmartVCD.Jpn (11/25/2019)
VXD	13	dsound.vxd (04/14/2008)	ndphlpr.vxd (02/21/2020)
TASKS	1	Microsoft.Common.Tasks (01/21/2008)	Microsoft.Common.Tasks (10/05/2019)
SEARCHCONNECTOR-MS	12	connectedsearch-music.searchconnector-ms (06/18/2013)	Microsoft Office Outlook.searchconnector-ms (02/15/2020)
DESKLINK	1	Desktop (create shortcut).DeskLink (09/18/2006)	Desktop (create shortcut).DeskLink (03/04/2020)
WPRP	1	provtrace.wprp (03/18/2017)	provtrace.wprp (03/18/2017)
GRL	2	Active.GRL (11/02/2006)	Active.GRL (03/18/2017)
HHK	19	merged.hhk (04/24/2017)	Index.hhk (11/28/2019)
ADML	215	WindowsMediaDRM.adml (11/02/2006)	OneDrive.adml (03/30/2020)
FTS	6	VBAACCSP.FTS (05/10/2017)	BS9532.FTS (05/10/2017)
BR2	1	M1033Eva.BR2 (03/18/2017)	M1033Eva.BR2 (03/18/2017)
DIAGPKG	1	DiagPackage.diagpkg (07/13/2009)	DiagPackage.diagpkg (03/18/2017)
ESN	3	noise.esn (04/14/2008)	noise.esn (04/14/2008)
GID	14	msaccess.GID (05/10/2017)	Wspelldlg.GID (01/10/2020)
CI	15	00010001.ci (04/24/2017)	extension.ci (01/02/2020)
EBD	3	systemsf.ebd (04/11/2009)	ResPriStaticDb.ebd (04/24/2017)
IDX	40	M1033DSK.IDX (09/18/2006)	psanbla.idx (03/05/2020)
DBL	1	wpa.dbl (04/24/2017)	wpa.dbl (08/29/2019)
EFTX	53	Apex.eftx (05/10/2017)	Trek.eftx (03/04/2020)
MYDOCS	2	My Documents.mydocs (04/24/2017)	Documents.mydocs (04/24/2017)
GMMP	4	Graphics.gmmp (09/18/2006)	Graphics.gmmp (03/18/2017)
CHS	2	NOISE.CHS (09/18/2006)	extension.chs (01/02/2020)
AUTOMATICDESTINATIONS-MS	4	f01b4d95cf55d32a.automaticDestinations-ms (04/24/2017)	5f7b5f1e01b83767.automaticDestinations-ms (04/24/2017)
ADM	24	conf.adm (04/14/2008)	AER_1033.ADM (01/29/2020)
CLB	7	R000000000001.clb (09/18/2006)	R000000000004.clb (02/21/2020)
THEME	42	Windows Classic.theme (09/18/2006)	index.theme (01/13/2020)
DYC	38	XBA55P_A.DYC (09/18/2006)	XWA75L_A.DYC (09/18/2006)
BLF	1	KtmRmTm.blf (04/24/2017)	KtmRmTm.blf (05/10/2017)
MAPIMAIL	1	Mail Recipient.MAPIMail (09/18/2006)	Mail Recipient.MAPIMail (03/04/2020)
ANI	113	drum.ani (11/02/2006)	pdf2html.ani (02/12/2020)
UCE	8	bopomofo.uce (11/02/2006)	bopomofo.uce (03/18/2017)
EVTX	192	HardwareEvents.evtx (04/24/2017)	Microsoft-Windows-Windows Defender%4Operational.evtx (03/30/2020)
PPD	1568	BRH24CE3.PPD (09/18/2006)	MSXPSINC.PPD (03/04/2020)

What are System Files?

Popular System File Extensions

File Database Breakdown - System File Extensions

Top System File Extensions