Safe mode & clean boot procedures - how to make use of them

Technical Level : Basic


I wrote this Wiki article because I could never see the wood for the trees when reading suggested procedures for running Safe mode & Clean boot.  I have tried to explain how you make use of these procedures not just how you do them.

Safe mode exists as an automatic fallback option for the OS if it is unable to boot properly. 

Users can boot into Safe mode deliberately in order to investigate problems.  Safe mode can be a useful tool for helping to identify their causes.  In Safe mode, Windows only loads a very basic set of drivers & Windows components.  It does not load third-party software.

  • In essence, if a problem continues to occur in Safe mode then the problem is caused by Windows itself or by the basic hardware drivers loaded in Safe mode. 

  • Conversely, if a problem does not manifest itself in Safe mode then the problem is being caused by Windows settings, hardware drivers or applications.

If Safe mode booting does not sufficiently identify the cause of a problem then a more methodical approach to narrowing down its cause can be adopted.  This is known as Clean boot.



Warning - Safe mode, Clean boot & the internet

This article contains several links to online information.  These should be read beforehand, and possibly printed to PDF, unless another computer is going to be available for reference during the Safe mode & Clean boot procedures.

  • Windows Defender does not protect your computer during Safe mode - it does not run its Real time protection function.

  • The services disabled during most of the Clean boot procedures will prevent Windows defender running correctly if it runs at all.

1          Booting into Safe mode

1.1       The procedure for booting into Safe mode is not the same as it was in earlier versions of Windows.

1.2       I use the procedure in section 3 of If the Admin prompt has a greyed out or missing Yes button but no password entry box, use the Built-In Admin account in Safe mode to create two new Admin accounts - Wiki.

1.3       If you use the equivalent TenForums procedure then I suggest bypassing the use of MSConfig if possible because users have, in certain circumstances, found themselves locked into Safe mode.  They could not boot normally until they had completed the procedures in Escape from Safe mode boot loop using an installation disk - Wiki.

2          Making use of Safe mode

2.1       If the problem does not occur in Safe mode then the process of narrowing down its cause can start off by comparing elements relevant to the problem in Safe mode with their behaviour during normal running.  You can use Device manager, Event viewer, RegEdit & most of Settings [but not its Update & security section].

  • This approach could only apply if suspicion had already fallen on particular things. 

  • If there are no prime suspects then more comprehensive & systematic procedures need to be used to narrow down the cause of the problem i.e. Clean boot, see sections 3 & 4 below.

2.2       If the problem does occur in Safe mode as well then you should consider the system-wide recovery options available to you. 

2.3       Safe mode can be used to conduct specific tasks that cannot be accomplished in normal running.

  • As the Wiki article [para 1.2 above] illustrates, one use of Safe mode can be to recover system access despite corruption of all Admin users’ account profiles.

  • You might be able to uninstall an application in Safe mode that you could not uninstall during normal operations.  If you get a Windows Installer service error you should refer to the Microsoft guide in para 3.1 below.

  • Beware of running malware scans in Safe mode.  Your anti-malware application might not run correctly in this mode.  Malwarebytes, for example, is not designed to run in Safe mode.  The online Microsoft Safety Scanner does run correctly in Safe mode. 

  • Windows Defender can run scans using its old user interface [C:\Program Files\Windows Defender\MSASCui.exe] in Safe mode but I have been unable to find any confirmation that it scans effectively.  If you cannot boot normally in order to use it then you might be better off creating the standalone Windows Defender Offline tool on another computer. 

3          Running Clean boot

3.1       Microsoft’s guide to using Clean boot is in How to perform a clean boot in Windows - Windows help.  I find it useful to start off by scanning down this article clicking on the dropdown arrows to expand the parts relevant to Windows 10 and only then to read it through properly.

3.2       The TenForums guide to using Clean boot is in Perform a Clean Boot in Windows 10 to Troubleshoot Software Conflicts - TenForums

3.3       Both suggested procedures make use of MSConfig, a tool that is not quite the same as it was in previous Windows versions.  There is no particular need to study the tool at this stage because the relevant procedures explain what to do with it during Clean boot.  You can run MSConfig from C:\Windows\System32\msconfig.exe.  There is a guide to it in the Wiki article MSConfig the System Configuration Tool [an article that MS endorses - see How to open MSConfig in Windows 10]. 

4          Making use of Clean boot

4.1       In brief, during Clean boot, you start off by disabling all Microsoft services [MSConfig], disabling all Start-up items [Task manager] and then restarting the computer. 

4.2       If the problem does occur in the first Clean boot restart then you should consider the system-wide recovery options available to you [described in para 2.2 above].

4.3       If the problem does not occur in the first Clean boot restart then the guides steer you through forcing the problem to reappear & thus identifying its cause. 

  • This involves gradual re-enabling of Task manager Start-up items & MSConfig Services until the fault reappears thus identifying the last change made as its cause. 

  • This is time-consuming.

4.4       If Clean boot identifies the root cause of the problem but a solution is not apparent then I suggest posting a question in the forum to seek help. 

  • Create a new question of your own because simply tagging onto an existing one attracts very little attention, invites confusion & misinterpretation and tends to yield poorer responses. 

  • In a question of your own you can state the problem symptoms, describe the computer & its setup and explain the troubleshooting steps you have already taken. 

  • Always include a statement of the OS Edition-Version-Type, such as Windows 10 Home Ver 1703 32-bit.  You can get the relevant Windows information by entering WinVer in a Command prompt window & by viewing Settings, System, About [which takes some time to appear].

  • Include the name & version of anything else you think is relevant such as hardware drivers or applications.  You can get hardware information in Device manager.

  • Include diagrams, such as screenshots, by clicking on the picture icon in the toolbar at the top of the editing box.

  • Try to impart as much understanding as somebody who had been looking over your shoulder would have acquired.

  • Please remember that this is a user-to-user mutual assistance forum for MS products in which users ask questions and users answer questions. 

  • Ranting about MS hinders assistance by distracting readers’ attention away from your problem.

  • Take care when selecting the dropdown choices underneath your question text because they determine the forum section in which your question appears.  Many forum contributors display lists of the latest questions in the topics they have expertise in so posting your question in the wrong section can stop it being seen by the very people who could help you.

  • If you get a reply that does not help then post again to say so in order to inform those that might be able to help you.  Ignoring unhelpful replies can create the impression that they were indeed helpful & that the problem might even have been solved.


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Last updated April 8, 2021 Views 10,381 Applies to: