CCleaner (; originally meaning "Crap Cleaner"), developed by
Piriform Software
Piriform Software Ltd. is a British software company based in London, owned since 2017 by Avast which itself became part of Gen Digital in 2022. The company develops cleaning and optimisation tools for Microsoft Windows, macOS and Android (opera ...
, is a
utility
In economics, utility is a measure of a certain person's satisfaction from a certain state of the world. Over time, the term has been used with at least two meanings.
* In a normative context, utility refers to a goal or objective that we wish ...
used to clean potentially unwanted files and invalid
Windows Registry
The Windows Registry is a hierarchical database that stores low-level settings for the Microsoft Windows operating system and for applications that opt to use the registry. The kernel, device drivers, services, Security Accounts Manager, a ...
entries from a computer. It is one of the longest-established system cleaners, first launched in 2004.
It was originally developed for
Microsoft Windows
Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...
only,
but in 2012, a
macOS
macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...
version was released. An
Android version was released in 2014.
Features
CCleaner can delete potentially unwanted files left by certain programs, including
Microsoft Edge
Microsoft Edge is a Proprietary Software, proprietary cross-platform software, cross-platform web browser created by Microsoft and based on the Chromium (web browser), Chromium open-source project, superseding Edge Legacy. In Windows 11, Edge ...
,
Internet Explorer
Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated as IE or MSIE) is a deprecation, retired series of graphical user interface, graphical web browsers developed by Microsoft that were u ...
,
Firefox
Mozilla Firefox, or simply Firefox, is a free and open-source web browser developed by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. It uses the Gecko rendering engine to display web pages, which implements curr ...
,
Google Chrome
Google Chrome is a web browser developed by Google. It was first released in 2008 for Microsoft Windows, built with free software components from Apple WebKit and Mozilla Firefox. Versions were later released for Linux, macOS, iOS, iPadOS, an ...
,
Opera
Opera is a form of History of theatre#European theatre, Western theatre in which music is a fundamental component and dramatic roles are taken by Singing, singers. Such a "work" (the literal translation of the Italian word "opera") is typically ...
,
Safari
A safari (; originally ) is an overland journey to observe wildlife, wild animals, especially in East Africa. The so-called big five game, "Big Five" game animals of Africa – lion, African leopard, leopard, rhinoceros, African elephant, elep ...
,
Windows Media Player
Windows Media Player (WMP, officially referred to as Windows Media Player Legacy to retronym, distinguish it from Windows Media Player (2022), the new Windows Media Player introduced with Windows 11) is the first media player (application soft ...
,
eMule
eMule is a Free software, free peer-to-peer file sharing application for Microsoft Windows. Started in May 2002 as an alternative to eDonkey2000, eMule connects to both the eDonkey network and the Kad network. The distinguishing features of eM ...
,
Google Toolbar,
Netscape
Netscape Communications Corporation (originally Mosaic Communications Corporation) was an American independent computer services company with headquarters in Mountain View, California, and then Dulles, Virginia. Its Netscape web browser was o ...
,
Microsoft Office
Microsoft Office, MS Office, or simply Office, is an office suite and family of client software, server software, and services developed by Microsoft. The first version of the Office suite, announced by Bill Gates on August 1, 1988, at CO ...
,
Nero
Nero Claudius Caesar Augustus Germanicus ( ; born Lucius Domitius Ahenobarbus; 15 December AD 37 – 9 June AD 68) was a Roman emperor and the final emperor of the Julio-Claudian dynasty, reigning from AD 54 until his ...
,
Adobe Acrobat
Adobe Acrobat is a family of application software and web services developed by Adobe Inc. to view, create, manipulate, print and manage Portable Document Format (PDF) files.
The family comprises Acrobat Reader (formerly Reader), Acrobat (former ...
,
McAfee
McAfee Corp. ( ), formerly known as McAfee Associates, Inc. from 1987 to 1997 and 2004 to 2014, Network Associates Inc. from 1997 to 2004, and Intel Security Group from 2014 to 2017, is an American proprietary software company focused on online ...
,
Adobe Flash Player
Adobe Flash Player (known in Internet Explorer, Firefox, and Google Chrome as Shockwave Flash) is a discontinuedExcept in China, where it continues to be used, as well as Harman for enterprise users. computer program for viewing multimedia ...
,
Sun Java,
WinRAR
WinRAR is a trialware file archiver utility, developed by Eugene Roshal of win.rar GmbH. It can create and view archives in RAR or ZIP file formats, and unpack numerous archive file formats. To enable the user to test the integrity of archive ...
,
WinAce,
WinZip and
GIMP
Gimp or GIMP may refer to:
Clothing
* Bondage suit, also called a gimp suit, a type of suit used in BDSM
* Bondage mask, also called a gimp mask, often worn in conjunction with a gimp suit
Embroidery and crafts
* Gimp (thread), an ornamental tr ...
along with browsing history,
cookies
A cookie is a sweet biscuit with high sugar and fat content. Cookie dough is softer than that used for other types of biscuit, and they are cooked longer at lower temperatures. The dough typically contains flour, sugar, egg, and some type of ...
,
recycle bin, memory dumps, file fragments, log files, system caches, application data,
autocomplete
Autocomplete, or word completion, is a feature in which an application software, application predicts the rest of a word a user is typing. In Android (operating system), Android and iOS smartphones, this is called predictive text. In graphical us ...
form history, and various other data. The program includes a
registry cleaner
A registry cleaner is a class of utility software designed for the Microsoft Windows operating system, whose purpose is to remove redundant items from the Windows Registry.
Registry cleaners seem to no longer be supported by Microsoft, despite ori ...
to locate and correct problems in the Windows registry, such as missing references to shared
DLLs, unused registration entries for
file extensions
A filename extension, file name extension or file extension is a suffix to the filename, name of a computer file (for example, Text file, .txt, MP3, .mp3, .exe) that indicates a characteristic of the file contents or its intended use. A filename e ...
, and missing references to
application paths.
CCleaner 2.27 and later can
wipe the
MFT free space of a drive, or the entire drive.
CCleaner can
uninstall programs or modify the list of programs that execute on startup. Since version 2.19, CCleaner can delete Windows
System Restore
System Restore is a feature in Microsoft Windows that allows the user to revert their computer's state (including system files, installed applications, Windows Registry, and system settings) to that of a previous point in time, which can be used ...
points. CCleaner can also automatically update installed programs and computer drivers.
Piriform also distributes a
web browser
A web browser, often shortened to browser, is an application for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's scr ...
called CCleaner Browser, included as an optional add-on included within the CCleaner installer. The browser, built on Google's
free and open-source
Free and open-source software (FOSS) is software available under a Software license, license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term ...
project
Chromium
Chromium is a chemical element; it has Symbol (chemistry), symbol Cr and atomic number 24. It is the first element in Group 6 element, group 6. It is a steely-grey, Luster (mineralogy), lustrous, hard, and brittle transition metal.
Chromium ...
, includes built-in
ad blocking
Ad blocking (or ad filtering) is a software capability for blocking or altering online advertising in a History of the web browser, web browser, an Application software, application or a network. This may be done using browser extensions or othe ...
and
anti-tracking features. The browser is only available for
Microsoft Windows
Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...
. The browser is identical to
Avast Secure Browser
Avast Secure Browser (formerly Avast! SafeZone) is an Avast Software web browser included for optional installation in the Avast Antivirus installer since 2016, but it is also available on its website. It is based on the open source Chromium pro ...
, which is also owned by Piriform's parent company,
Gen Digital
Gen Digital Inc. (formerly Symantec Corporation and NortonLifeLock Inc.) is a multinational software company co-headquartered in both Prague, Czech Republic (European Union, EU) and Tempe, Arizona (United States, USA). The company provides comp ...
.
History
CCleaner was first launched in 2004 for
Microsoft Windows
Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...
.
It remained a Windows-only utility until 2012. On 2 June 2011, Piriform announced a public beta test program for CCleaner for
Mac
Mac or MAC may refer to:
Common meanings
* Mac (computer), a line of personal computers made by Apple Inc.
* Mackintosh, a raincoat made of rubberized cloth
* Mac, a prefix to surnames derived from Gaelic languages
* McIntosh (apple), a Canadi ...
. The Mac version graduated to the test stage on 30 January 2012.
A commercial Network Edition was also introduced. Piriform released CCleaner for
Android in 2014.
Critical reception
''
CNET'' editors gave the application a rating of 5/5 stars, calling it a 'must-have tool'. It was awarded ''Editor's Choice Award'' in April 2009 by CNET. In 2016 Piriform announced 2 billion CCleaner downloads worldwide. In January 2014 it had been the most popular software on
FileHippo
FileHippo is a software downloading website that offers computer software for Windows. The website has sections listing most recently updated programs and most popular downloads, organised by category, with program information and link. Registrat ...
for more than a year, and had a 5-star editor's rating o
download.zoneand
Softpedia
Softpedia is a software and tech news website based in Romania. It indexes, reviews and hosts downloadable software and reports news on technology and science topics. It is ranked as among of the top download portals on the internet.
History
So ...
.
CCleaner has been reviewed by ''
Chip.de'',
''
TechRadar
''TechRadar'' is an online technology publication owned by Future plc. It has editorial teams in the United States, United Kingdom, and Australia that provide news and reviews of tech products and gadgets. It was launched in 2008 and expanded t ...
'', ''
PC Magazine
''PC Magazine'' (shortened as ''PCMag'') is an American computer magazine published by Ziff Davis. A print edition was published from 1982 to January 2009. Publication of online editions started in late 1994 and continues .
Overview
''PC Mag ...
'' and ''
TechRepublic
TechRepublic is an online trade publication and social community for IT professionals, providing advice on best practices and tools for the needs of IT decision-makers.
It was founded in 1997 in Louisville, Kentucky, by Tom Cottingham and Kim S ...
''.
Data collection
Upon an error in the code, the Active Monitoring component of CCleaner 5.45, which was designed to measure junk levels to trigger cleaning, switched back on again. Piriform recognized this error and confirmed to users that the Active Monitoring feature did not report data. It then changed Active Monitoring to the more accurate title of 'Smart Cleaning'. After criticism later versions allowed data collection to be controlled separately by the user, although some data collection, such as OS and language, which is necessary for the app to be delivered, is still on by default as outlined in the company's Data Factsheet. Piriform states that the data collection is completely anonymous and is used to improve product quality.
Bundled software
Piriform was acquired by Avast in July 2017. In December 2018, it was reported that users installing CCleaner would also have
Avast Antivirus
Avast Antivirus is a family of cross-platform internet security applications developed by Gen Digital Inc. for Microsoft Windows, macOS, Android, and iOS. Avast offers free and paid products that provide computer security, browser security, an ...
installed without their permission, with TechSpot claiming this arguably made CCleaner no better than the malware it was supposed to defend against. Piriform denied this.
In July 2020, Microsoft
Windows Defender
Microsoft Defender Antivirus (formerly Windows Defender) is an antivirus software component of Microsoft Windows. It was first released as a downloadable free anti-spyware program for Windows XP and was shipped with Windows Vista and Windows 7. ...
began flagging the free version of CCleaner as a "
potentially unwanted application", stating that "while the bundled applications themselves are legitimate, bundling of software, especially products from other providers, can result in unexpected software activity that can negatively impact user experiences." Piriform rolled out an update days later and third-party software installation is now optional when installing the program.
Malware infection
After
Piriform was acquired by
Avast
Avast Software s.r.o. is a Czech multinational cybersecurity software company headquartered in Prague, Czech Republic, that researches and develops computer security software, machine learning, and artificial intelligence. Avast had more th ...
, in September 2017, CCleaner 5.33 was compromised by the incorporation of the Floxif
trojan horse
In Greek mythology, the Trojan Horse () was a wooden horse said to have been used by the Greeks during the Trojan War to enter the city of Troy and win the war. The Trojan Horse is not mentioned in Homer, Homer's ''Iliad'', with the poem ending ...
into the distributed program that could install a
backdoor, enabling remote access to 2.27 million machines which had installed CCleaner.
Avast insisted that the malware was already in CCleaner version 5.33, prior to the purchase of Piriform. Forty of the infected machines received a second-stage payload that appears to have targeted technology companies
Samsung
Samsung Group (; stylised as SΛMSUNG) is a South Korean Multinational corporation, multinational manufacturing Conglomerate (company), conglomerate headquartered in the Samsung Town office complex in Seoul. The group consists of numerous a ...
,
Sony
is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...
,
Asus
ASUSTeK Computer Inc. (, , , ; stylized as ASUSTeK or ASUS) is a Taiwanese Multinational corporation, multinational computer, phone hardware and electronics manufacturer headquartered in Beitou District, Taipei, Taiwan. Its products include deskto ...
,
Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...
,
VMWare,
O2,
Singtel
Singapore Telecommunications Limited, trading as Singtel, is a Singaporean telecommunications conglomerate, the country's principal fixed-line operator and one of the four major mobile network operators operating in the country.
Overview
T ...
, Gauselmann, Dyn, Chunghwa and
Fujitsu.
On 13 September, Piriform released CCleaner 5.34 and CCleaner Cloud 1.07.3191, without the malicious code.
On 21 October 2019, Avast disclosed a second security breach during which attackers tried again to insert malware inside CCleaner releases. The attempt was unsuccessful.
See also
*
Malware
Malware (a portmanteau of ''malicious software'')Tahir, R. (2018)A study on malware and malware detection techniques . ''International Journal of Education and Management Engineering'', ''8''(2), 20. is any software intentionally designed to caus ...
*
Utility software
Utility software is a program specifically designed to help manage and tune system or application software. It is used to support the computer infrastructure - in contrast to application software, which is aimed at directly performing tasks that b ...
References
Is CCleaner Worth Buying? A 2025 Perspective
External links
*
*
{{Gen Digital
Android (operating system) software
Computer system optimization software
Utilities for macOS
Uninstallers for Windows
Data erasure software
Utilities for Windows
Freeware
Piriform Software
2003 software
Companies' terms of service
Gen Digital software
Proprietary software
Freemium