We have launched a free online document viewer: Doconut.app. Drop a file on the page, read it in the browser, and it is deleted from our servers when you close the tab. No account, no install, no paid tier.

Origin of our Platform
It opens 70+ extensions across seventeen viewers — PDF, Word, Excel, PowerPoint, CAD, PSD, Visio, Project, email, EPUB, TIFF and the image formats — with the size ceiling set per format, from 5 MB for XML and HTML up to 25 MB for PDF, PSD and images.
What it does not do is equally worth stating: it does not convert files, edit them or store them, and it takes one at a time.
The synergy with Doconut.com
The rendering engine is the Doconut .NET SDK, the commercial component sold at Doconut.com for developers who need document viewing inside their own applications. This site runs on it.
That is the honest explanation for why a capable viewer is free: it is the place you can try the engine on a real file without a licence or an installer. If it renders your awkward document well here, it will render it well in your application.
Final thoughts
Try it with the file that is currently stuck — Doconut.app. The formats worth testing first are the ones nothing else opens: a layered PSD, a DWG drawing, an Outlook .msg.
Yours Truly,
Doconut Team