Component-Based Servicing (cbs.log) causes all drive space to be consumed

Because I’ve seen this question asked in many places and not answered, I thought I’d post my issue and resolution here.  I regard this as a Bug, but I’m not invested enough to deal with the support incident process.

I’ve had repeated instances where a Windows 7 x64 client runs out of hard drive space, and found that C:\Windows\TEMP is being consumed with hundreds of files with names following the pattern “cab_XXXX_X”, generally 100 MB each, and these files are constantly generated until the system runs out of space.  Upon removing the files & rebooting, the files start being generated again.

I’ve found that this is caused by large Component-Based Servicing logs.  These are stored at C:\Windows\Logs\CBS.  The current log file is named “cbs.log”.  When “cbs.log” reaches a certain size, a cleanup process renames the log to “CbsPersist_YYYYMMDDHHMMSS.log” and then attempts to compress it into a .cab file.

However, when the cbs.log reaches a size of 2 GB before that cleanup process compresses it, the file is to large to be handled by the makecab.exe utility.  The log file is renamed to CbsPersist_date_time.log, but when the makecab process attempts to compress it the process fails (but only after consuming some 100 MB under \Windows\Temp).  After this, the cleanup process runs repeatedly (approx every 20 minutes in my experience).  The process fails every time, and also consumes a new ~ 100 MB in \Windows\Temp before dying.  This is repeated until the system runs out of drive space.

This can be reproduced by trying to manually create the cab file –

Directory of C:\CBS-BAK
12/11/2019  12:28 PM    <DIR>          .
12/11/2019  12:28 PM    <DIR>          ..
12/11/2019  12:12 PM     2,491,665,966 CbsPersist_20150823021618.log

C:\CBS-BAK>makecab CbsPersist_20150823021618.log
Cabinet Maker – Lossless Data Compression Tool
86.19% – CbsPersist_20150823021618.log (1 of 1)
ERROR: (FCIAddFile)Data-size or file-count exceeded CAB format limits

C:\CBS-BAK>dir %TEMP%\cab*
Volume in drive C is OSDisk
Volume Serial Number is 44DE-0CDD
Directory of C:\Users\USERNAME\AppData\Local\Temp
08/26/2015  02:31 PM       102,786,654 cab_4556_2

12/11/2019  12:28 PM        12,978,919 cab_5860_2
12/11/2019  12:27 PM                 0 cab_5860_3

To resolve this –

Stop the Windows Modules Installer (TrustedInstaller) service

Delete or move the large Cbspersist_XX.log file out of \Windows\Logs\CBS.

Start the Windows Modules Installer (TrustedInstaller) service

How to Disable/Enable Internet Options Tabs in Internet Explorer

As an IT guy, I always encounter problems when untrained users tweak their Internet connection settings.  They always make a mistake somewhere and sometimes the solution is to just keep them away from the Internet Options dialog box altogether.

I have worked at many companies that hide the Internet Options tab in Internet Explorer to discourage users from changing the options, which makes sense since network admins are the only ones who are supposed to access these options.

In a controlled environment, companies usually allow only one type of browser like Internet Explorer and those companies usually don’t allow their employees to change the Internet Options like default the homepage and proxy server.

Below is a typical Internet Options window:

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There are several ways to disable the Internet Options tabs in IE and I’ll explain the different methods in this post. The first method uses Group Policy, but will only work if you have the Pro or Ultimate versions of Windows. If you are running Home or Home Premium, then skip down to the registry section.

Disable Internet Options in IE via Group Policy

To disable any tab in the Internet Options window, follow these steps below:

Step 1: Click Start and type GPEDIT.MSC in the search bar and hit enter to launch the Group Policy editor window.

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Step 2: In the Local Group Policy editor window expand User Configuration > Administrative Templates > Windows Components > Internet Explorer then click on Internet Control Panel.

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Step 3: On the right pane of the window, double click on the item you want to disable. For example, to disable the Advanced tab, double click on Disable the Advanced page option.

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Step 4: In the properties window, click on the Enabled option and click OK. The Advanced tab in the Internet Options window will now be disabled and removed.

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Step 5: Follow the previous steps to disable other items in the Internet Options window. To enable items, just select the Not Configured option in the properties window and click OK.

There you have it!  For less savvy computer users who don’t know about GPEDIT, it should discourage them from changing the advanced settings in IE.

Disable IE Options via Registry Editor

The second way to disable tabs in IE options is to use the registry editor. This is a bit more complicated, but is the only option if you can’t access group policy editor.

You can open the registry editor by clicking on Start and typing in regedit. Once there, navigate to the following key:

HKEY_CURRENT_USER\Software\Policies\Microsoft

Note that if you want to disable this option for all users on the PC, navigate to the same key, but under HKEY_LOCAL_MACHINE.

If there isn’t already a key called Internet Explorer under Microsoft, you’ll have to create it manually. Just right-click on Microsoft and choose NewKey. At this point, there are two options. If you want to disable the entire Internet Options dialog, you can create another key under Internet Explorer called Restrictions.

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Lastly, you’ll create a new DWORD value in the right-pane inside Restrictions called NoBrowserOptions. Give that a value of 1 and restart Internet Explorer. If you try to go to Internet Options, it will give you an error message.

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If you don’t want to disable the whole dialog, but instead just a few of the tabs, then you should create a new key called Control Panel under Microsoft instead of Restrictions. Inside of that, you’ll create DWORD entries that correspond to the tabs:

AdvancedTab

ConnectionsTab

ContentTab

GeneralTab

PrivacyTab

ProgramsTab

SecurityTab

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As you can see above, I created the Control Panel key under Internet Explorer and then created a DWORD entry in the right-pane called AdvancedTab with a decimal value of 1. This removed just the advanced tab from the IE options window.

Hopefully, these methods will allow you to gain more control over Internet Explorer advanced settings in your environment. If you’re having issues, feel free to comment and I’ll try to help. Enjoy!