Category Archives: Technical

“Rational” IT related entries.

macOS High Sierra doesn’t start after updating (stuck on Apple logo) — “failed to unwrap volume key” error

Posted on July 14, 2019 by Dae

The first thing you want to do when your Mac system doesn’t start is to start up into the verbose mode to see if there any error messages. Don’t try to fix the problem before diagnosing!

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Windows Server 2019: RD Session Host — ChangeMode “Invalid operation” exception

Posted on May 3, 2019 by Dae

If you’re changing the client access licensing mode of your RD Session Host using the PowerShell $obj.ChangeMode(…) command and it fails with an error saying “Exception … Invalid operation”…

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“Install %OS%.app does not appear to be a valid OS installer application” (createinstallmedia error)

Posted on May 2, 2019 by Dae

If you’re trying to create a bootable installer for an older macOS version (like El Capitan) with createinstallmedia, and it fails with a “does not appear to be a valid OS installer” error, quite possible the actual problem is that … Continue reading →

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Downgrade any Homebrew package easily

Posted on March 21, 2019 by Dae

Update from 2020: the instructions for tesseract don’t work anymore, see comments from other users below the post. I’ll use Tesseract as an example, but the same logic can be applied to any other Homebrew package.

Posted in How to’s | Tagged , | 14 Comments

“MagickWand shared library not found” on uwsgi

Posted on January 13, 2019 by Dae

If you’re getting this error while deploying a Python app on uwsgi: MagickWand shared library not found. You probably had not installed ImageMagick library. Try to install: apt-get install libmagickwand-dev It may not be what it seems: Wand’s load_library() function … Continue reading →

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Make VLC show the title of a streaming video

Posted on September 19, 2018 by Dae

I’ve created a tiny VLC extension that makes VLC show the title of the currently playing streaming video. It allows you to set custom titles even for the streams that you don’t own (e.g. from YouTube). For more information, see: … Continue reading →

Posted in Releases | Tagged , | 5 Comments

Kerio Connect server connection errors after upgrading to version 9.2.6

Posted on May 23, 2018 by Dae

Kerio Connect 9.2.6 introduced a limit for a number of simultaneous connections from a single IP address, which is — by default — set to 100 per protocol. If more than a hundred of users start using Kerio Connect from … Continue reading →

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Make tojson filter in Jinja2 output Unicode instead of escape sequences

Posted on January 27, 2018 by Dae

This wasn’t documented anywhere, but kudos to the Jinja2 devs for making this so easy to figure out from the source code.

Posted in How to’s | Tagged | 2 Comments

Fixing Windows Update: what to do when wuauserv refuses to stop

Posted on August 20, 2017 by Dae

Every now and then my virtualized Windows 10 would stuck at “Checking for updates” or “Downloading updates: 0%”. The solutions on various websites suggest stopping the related system services (net stop wuauserv and net stop bits) and trashing the contents … Continue reading →

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Where does the AppStore version of DaVinci Resolve Studio 12 store its projects?

Posted on June 19, 2017 by Dae

Make sure to make regular backups of this folder:

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