Category Archives: Technical

“Rational” IT related entries.

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

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

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 , | 13 Comments

“MagickWand shared library not found” on uwsgi

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

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

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

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

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?

Make sure to make regular backups of this folder:

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How to load VirtIO storage drivers in Windows System Restore

If you need to load VirtIO block storage driver (aka viostor) in Windows System Restore (aka Windows Recovery Mode) to recover your Windows virtual machine, take the following steps. (Also please read my note below).

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How to add an existing virtual disk to Proxmox

It’s trivial to create virtual disks in Proxmox, but what if you want to add an existing disk to a new virtual machine?

Posted in How to’s | Tagged , | 7 Comments