Open a command prompt (cmd.exe) and type:

attrib +h +s +r %localappdata%\Microsoft\Windows\History

and apply the command (return). This should be all you have to do. You have to reopen a new IE window to see the fixed result.

Background:

The initial settings for the History folder are +h +s +r (hidden, system, read-only). If the folder gets removed, IE recreates it, but doesn't set these attributes. Either setting +r or +s will make it show as "History view". However, as the original setting is hsr we want to make it hsr if we can ... Once +r or +s is set the desktop.ini lying in that folder will be used to create the special "History view" for that folder. Windows Explorer behaves the same as Internet Explorer in this respect. If you open the folder in Windows Explorer and it shows a desktop.ini and other files or folders the "magic" view is gone. If you get the "History view" in Windows Explorer you can be certain that you also get it in Internet Explorer.

The target for all three of these is actually the same (e.g. they mutually set each other) and is not the same as the prefilled path for the "Save" option of the download manager. The folder prefilled for "Save as" is always the folder that you saved to by either one of the three options above and is tracked by one of the many MRU (most recently used) lists that Windows is taking care of. With the help of ProcMon I found out that this is the correct registry location for this path:

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\ComDlg32\LastVisitedPidlMRU

It holds the "last saved" directory not only for IE, but for WE and maybe other applications as well. In order to not "confuse" Windows with missing numbers I suggest that you simply delete all entries with the exception of the default entry on top of this key. This has the side effect that other applications will also forget this setting and present the default saving path the next time. Not really a problem. Once you did this and reopen IE and try to save again by one of the options above it should go to the default path for that action (which depends on the file type, e.g. if you want to save a gif picture it should go to your Pictures library).

Bonus:

The path for the "Save" option in download manager can be set if you open the download manager and click "Options". This shows a field for "Default download location" that can only be set by "browsing", not by typing. Unfortunately, it doesn't show the full path, only the folder name. If you want to see the real path, you have to click "Browse". The original default location can be seen by using "shell:downloads" (it defaults to %userprofile%/downloads).

Since IE11 there is a difference in the user-agent string that IE sends to the site (it's much shorter and doesn't contain most add-ons) and the user-agent string that IE reveals to Javascript applications running in the browser itself (there it reveals more information, basically the same it always used to give).

With IE11 there also was a major change in how IE identifies itself as IE. Many sites can't still cope with this and misidentify IE as an "old" browser that doesn't support the sites' "modern" features (although it does!).

With IE10 there was also revealed another flaw in many sites browser detection scripts: they never envisioned there could ever be an IE version higher than 9 (e.g. double-digit), so they misidentify IE10 as IE1 ...

Well maintained sites avoid both of these problems by not using browser detection at all. Instead they use "feature detection", e.g. they check if a certain functionality is available or not before using it, instead of using the inaccurate way of checking for the browser version (and then rule out support because of wrong premises).

If you need to further check for Flash availability, there is a test page available from Adobe at http://www.adobe.com/de/software/flash/about/ It shows the version information in a box. If it can do this your Flash is very likely to be working (say 99,9%). It also shows a red, animated "F" above that box. If that is not working you may have hit one of the very rare cases where Flash seems to be installed correctly, but isn't working (maybe another add-on or a security program is hampering it). Make sure that you have tracking protection and ActiveX filtering off for the adobe.com site. You can see if it is enabled in the browser address bar. You can disable it per site in the addressbar or globally in the safety menu of IE. There are some screenshots about this functionality (taken from IE9 where it was first introduced) here: http://winware.org/en/screenshots.php

Note, that since Windows 8 Flash is "included" with IE. That means it is still programmed and provided by Adobe but distributed as a pre-installed ActiveX component with IE/the OS. It is also upgraded via Windows Update coming with IE security updates and not from Adobe anymore (but the code etc. still comes from Adobe, so if it's not functioning correctly, don't blame Microsoft, Flash is still being coded by Adobe!). Because of that for some time there was no way of re-installing a non-working Flash component in IE coming with Windows 8 and up. However, as there have been quite a few problems with the pre-installed Flash upgrades Adobe has started to provide a Windows installer program that contains the latest released Flash code that came with the latest IE cumulative security upgrade. These Flash Player versions can be downloaded from here http://www.adobe.com/products/flashplayer/distribution3.html 

A word of caution for all people not on Windows 8 (and up) who update their Flash component. There was a time (some years ago) where Adobe did the right thing and provided updates right away within their install manager component. That was quick and without much hassle. However, some time ago they got greedy and started to redirect all upgrade attempts to their "download center" at http://get.adobe.com/flashplayer/ which requires a complete installation process for you in each and every upgrade case (e.g. once a month). The sheer purpose of this seems to get money from Google by trying to piggy-back the Google Chrome browser and the Google Toolbar. I strongly advise to uncheck these options before starting the download. Also, when running the setup make sure you use the "custom installation" variant and check if there's even more stuff that Adobe wants to install.

You may need to try some variation of the sequence below. If you can't make it work, please start a new thread on Microsoft Community and provide as much information as you can (especially about everything you tried to fix it, describe in detail!). The following was written with IE10 and Windows 8 in mind (at that time). It can also be used for IE11 (and maybe the next versions) and also for Windows 7 (so, you didn't upgrade the OS).

To correctly enable IE10/11 after an upgrade to Windows 8 (or 8.1 or 7) on a machine that had another browser as the default browser and had probably removed access to IE8/9:

- enable IE in Control Panel/Programs and Features/Turn Windows features on or off

- in Control Panel/Default Programs/Set program access and defaults: set the Microsoft Profile as the default (Do not use the "set your default programs" link! In most cases that cannot fix your problem, it merely associates the browser with a certain type of file or protocol!)

As a variation, try disabling the IE10 feature, let IE10 "uninstall", reboot and then "reinstall" it the same way. There may be other variations.

Please note, that if IE10 is "available", but does not work correctly (it starts for a second and "flashes" away without an error message or works for some time and then regularly crashes (it "encountered an error and needs to close") this is a completely different problem (and a different fix). The procedure to troubleshoot this problem is explained in the FAQ "How to troubleshoot a crashing IE".

Troubleshooting steps:
1. run IE in "No Add-Ons" mode (*)
2. disable third-party extensions in Internet options/Advanced
3. boot Windows in safe mode (with networking) (**)

If any or a combination of the above solves your problem there is third-
party software responsible for your problem. Note: you have to surf in
each step long enough to identify if the problem persists or not and
keep that functionality switched off when you change to the next step.
Just booting into safe mode and then back to normal won't achieve
anything.
If 1.: use Add-Ons-Manager, show all add-ons and disable all non-Microsoft add-ons and 
       reenable them step-by-step until your problem comes back
If 2.: that's likely a toolbar or some other installable add-on
If 3.: that's likely a third-party software run from startup that can but
       doesn't need to have "visible" connections to IE, for instance
       a so-called desktop search.
Go thru *all* steps! Don't tell us "I don't have any add-ons". You sure have!

If you want to avoid going thru all add-ons in step 1 you can also simply reset IE completely at Internet options, advanced. This will disable all your add-ons. You still have to do steps 2 and 3 if this didn't fix your problem!

* you can run IE in no-addons mode from Start Menu/Run or a command prompt with "iexplore -extoff"

** AFAICS, there is no safe mode with networking available from the F8 boot screen on Windows 8 (there is only a general safe mode without networking it seems). You can achieve this mode via msconfig and choosing "Diagnostic startup" on the General tab or Safe Boot on the Boot tab.

Note, that there can also be a difference between safe mode and safe mode with networking. If IE starts with networking disabled, but not with networking enabled then the problem is likely with the network drivers. (Trying without networking support usually doesn't make sense, but in this case it makes!)

If the method above does not work for you, try walking slowly and carefully through it again. It is really highly unlikely that you are the exception where it doesn't work.

Tip: If you want to have Start Menu/Run on Windows 8, you can install Classic Shell.

The default is Notepad. The problem starts when you want to choose a program that is not in the editor programs list for Internet options, Programs, for instance Notepad++. Once there was a simple way to add programs to this list (OpenWithList). This method doesn't seem to work anymore. I'll write more about this way once I know it works now.

The only way to set your preferred View Source editor I know of at the moment is to do it via registry. It's done in almost the same way you did that with IE7 (or Windows XP, for that matter). Set the Default value in HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Explorer\View Source Editor\Editor Name to the path of your preferred program. Make sure you use the HKCU hive (for the current user) and not the HKLM hive (for the whole machine). This is the main change here (all older tutorials will mention HKLM as the hive to change). This will not put your editor in the editor Programs listbox, but it will launch your preferred View Source editor from now on.

Beware: Do not set the "HTML editor" via the Programs listbox after you set the View Source editor. This will overwrite your changes and you are at square one. As long as you stay away from the listbox the two settings will remain different.

Standard ist hier Notepad. Probleme ergeben sich, wenn man ein anderes Programm (z.B. Notepad++) benutzen will, das nicht in der Liste für HTML-Editoren aufgeführt wird. Es gab früher eine einfache Möglichkeit, diese Liste zu befüllen (OpenWithList). Diese scheint es nicht mehr zu geben. Sobald ich mehr dazu weiß, werde ich das hier schreiben.

Der mir momentan einzig bekannte Weg, um den Quelltext-Editor (und nur diesen) zu setzen, führt über die Registry. Folgen Sie den Instruktionen hier: Quelltext-Editor einstellen. Ändern Sie aber nicht im Schlüssel-Bereich HKLM (ganze Maschine), sondern im Schlüsselbereich HKCU (aktueller User), also in HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Explorer\View Source Editor\Editor Name. Sonst wie im Artikel beschrieben. Die dort erwähnte Einstellung der OpenWithList übergehen Sie ebenfalls. Diese Änderung setzt zuverlässig den Quielltext-Editor auch beim IE11.

Achtung: Nach dieser Änderung dürfen Sie keinesfalls den HTML-Editor unter Internetoptionen, Programme ändern. Wenn Sie das tun, wird automatisch auch die Einstellung für den Quelltext-Editor überschrieben. Solange Sie diese Auswahl in Ruhe lassen, bleiben die beiden Editoren unterschiedlich eingestellt.

Beachten Sie, daß der IE dann mit den meisten Einschränkungen läuft, denen auch der Modern UI/Kachel-IE10 unterliegt, d.h. Flash funktioniert dann nur noch auf Seiten, die in der sog. CV list enthalten sind und die meisten Add-Ons funktionieren dann gar nicht mehr (nur noch diejenigen, die mit dem 64bit-Modus kompatibel sind).

Auf Nachfrage möchte ich gerne ganz klar betonen, daß es ab dem IE10 keine zwei Versionen des IE für 32bit und 64bit mehr gibt. Standard ist die 32bit-Hybrid-Version. Wer mehr "Sicherheit" will und dafür Einschränkungen in Kauf nimmt, kann den EPM aktivieren. Dieses Nebeneinander von zwei verschiedenbittigen Versionen des IE früher ist historisch gewachsen und war nie sinnvoll.

Between the automatic downloads the list is kept in local store and used from there. You can edit this list and add any new sites you wish to use Flash on. At the same time you lose the automatic updating of this list, so your local copy gets outdated over time. This does not only apply to Flash, but to other content as well. So, you may end up with sites that do not display correctly for you anymore, either because they were not removed from or were not added to your local copy of the CV list. Please bear this in mind when you start editing the file. When you observe problems with a site, first check if the problem couldn't be caused by absence/presence of the site on the CV list and always mention that you are not using the up-to-date CV list when you ask for help!

Now for what you came here :-)

The basic procedure is

1. stop updating of the CV list
2. edit the local copy
3. flush the IE cache

Steps in detail

In desktop mode IE press ALT, go to the Tools menu, click Combatibility View Settings, uncheck the mark "Download updated compatibility lists". Clock "Close". (Do not try to add sites manually in this dialog, it will not work for Flash.) Close all IE instances.

Open Notepad. Open Windows Explorer, type the following in the address bar: "%localappdata%\Microsoft\Internet Explorer\IECompatData\", hit Enter. This opens to a folder in your profile that should contain a single file: iecompatdata.xml. Drop this file on Notepad.

Open Edit and Search for "/flash", this sets you at the end of the "Allow Flash" section in the list. Now you can add any of your desired sites right before the closing "</Flash>" tag as <domain>example.com</domain>. Most easily done by a copy and paste of the last entry in the list. You can only enter raw domain and host names, no paths, protocols, slashes etc. When you are finished save the file and close Notepad.

As a last step we now have to flush the internet cache. First flush the cache of desktop IE at Internet options, General, Browsing history. Click the Delete button and check the first four categories, click Delete. Once IE is finished go to the Modern UI, open IE on it, open the Charms Bar, click Settings, click Internet options, click Delete button beneath Delete Browsing History section. Once this is finished close the IE app and reopen it.

You should now be able to view Flash content on all sites that you added to your local CV list. I verified that this works with the modern UI IE on Windows 8. I do not know but assume it works on RT devices as well (please use comments to confirm).

Remember what I said about your local CV list growing obsolete over time! You may want to update the list from time to time. To do so rename your existing file, reenable the automatic download of the list and wait. You may need to flush your cache again and visit at least one website. I can't tell you the exact order of steps, but after a few minutes of trying this and that the list suddenly appeared. Now you can "reinoculate" the updated CV list with your desired sites.

First check if that occurs only on some specific sites.

Test here: http://www.adobe.com/software/flash/about/
- if this shows a Flash-Version and the bouncing die, then test here: http://winware.org/en/browsercaps.php
- if this shows that ActiveX and Flash are active and there's also a version no. showing, then everything is okay.

If not, then check if ActiveX Filtering or Tracking Protection are enabled. ActiveX Filtering has to be off for sites that you want to allow Flash. Tracking Protection can have the nasty side effect, that certain elements of a page cannot be shown, including Flash content. Here are screenshots that show how you can see if these filters are enabled and how to switch them off/on either for specific sites (you can also control them globally, iof you want).

The above applies to the desktop version of IE10 on Windows 8. The modern UI version (metro, tiles) has the following limitation. Flash will only be shown, if the site is on the so-called CV list. This list is maintained by Microsoft and sites can apply for it with Microsoft. Sites can also force "modern" IE to show a prompt to change to desktop mode for Flash content. (This is an easy way to support Flash without being on the CV list.)

There is one more limitation for IE on Windows RT devices: the CV list requirement applies for the desktop mode as well (e.g. IE on Windows RT will show Flash content only on CV list sites, no matter which mode you use).

There does exist a way to edit the CV list manually. I will explain this in another article.

You can watch details for Flash in desktop IE with "Manage Add-Ons". Choose to display all add-ons in "Manage Add-Ons", then highlight the "Shockwave Flash" add-on. You'll see some info like version information in the lower pane now. You can watch more information (for instance the sites allowed) by clicking the link "More Information" in that lower pane. (An asterisk "*" means you allowed all sites.)

Important: the Flash player is a built-in "Microsoft third-party component" in IE10 on Windows 8/RT and gets updated via Windows Update. You cannot and should not try to install a downloaded Flash player from Adobe!

Adobe Information: Flash on Windows 8, Flash on Windows RT

Developer information from Microsoft: Developer Guidance for Web Sites with Flash Content in Windows 8, Web Sites and a Plug-in Free Web, how to apply for the CV list