If no plans to uninstall, can Log and Update Cache folders in Setup Bootstrap folder be removed?

by Solomon Rutzky   Last Updated January 10, 2018 21:06 PM

I have several versions of SQL Server, used for testing, installed on my laptop (2012, 2014, 2016, and 2017). I noticed the other day that there was a folder containing prior versions of files across updates (SPs, CUs). Across all versions there is actually quite a bit of space being taken up:

(all folders below reside within: C:\Program Files\Microsoft SQL Server\ )

110\Setup Bootstrap\Log - 1.09 GB (3,490 files)
110\Setup Bootstrap\Update Cache - 8.67 GB (13,251 files)

120\Setup Bootstrap\Log - 507 MB (2,741 files)
120\Setup Bootstrap\Update Cache - 4.8 GB (11,049 files)

130\Setup Bootstrap\Log - 369 MB (2,412 files)
130\Setup Bootstrap\Update Cache - 2.88 GB (6,875 files)

140\Setup Bootstrap\Log - 41.8 MB (385 files)
140\Setup Bootstrap\Update Cache - 351 MB (784 Files)

Totals for those folders are (MB have been normalized to GB):

Folder          GB          Files
----------     -----        ------
Log             1.99         9,028
Update Cache   16.69        31,959

TOTAL          18.68        40,987

Initially I figured that it should be safe to remove the Log and Update Cache folders, but then I reckoned it best to first check to see if others have asked this and if so, what the answer(s) had been. I found this KB article:

Description of the Update Cache folder in SQL Server

which states:

What happens if you remove this folder or delete its contents?

If the Update Cache folder or some patches are removed from this folder, you can no longer uninstall an update to your SQL Server instance and then revert to an earlier update build. In that situation, Add/Remove Programs entries point to non-existing binaries, and therefore the uninstall process does not work. Therefore, Microsoft strongly encourages you to keep the folder and its contents intact.

Ok. I have no plans to ever downgrade or uninstall an SP or CU, so I should be ok, right? Well, there are other references, such as this one:

Is it safe to delete the "Update Cache" folder?

in which someone referenced the following KB article:

How to restore the missing Windows Installer cache files and resolve problems that occur during a SQL Server update

which states (emphasis added):

When you install SQL Server, the Windows Installer stores critical files in the Windows Installer Cache (default is C:\Windows\Installer). These files are required for uninstalling and updating applications.

Now, this particular article seems specific to the C:\Windows\Installer folder, and I am not talking about deleting from that folder. Still, due to the mention of the possibility of not being able to apply updates, I wanted more info first.

Has anyone removed these folders before? If so, were there any negative effects? These folders only ever increase, and I was just about to apply the "Specter" CUs for both 2016 and 2017 (meaning those totals shown above are about to increase again for 2 of the 4 versions).

To be clear, I am not looking for should I or shouldn't I remove one or both of these folders; I am looking for can I or can't I remove one or both (without breaking anything more than the ability to uninstall / downgrade, which I already accept as a consequence).

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