There's nothing appearing in my extension manager

I think you find the problem!

Unfortunately not.
Your folder-options is set to not show file types.
So the ā€˜extension_managerā€™ file has no ā€œ.htmlā€ file type showing - but the ā€˜Typeā€™ column to the right shows its type - although you have clipped off the right-hand side, it is still clearā€¦

Try double clicking its icon and report what the web page that opens looks likeā€¦

Can it be fix?

Going back several posts you have still not confirmed that you have run a ā€œRepairā€ā€¦
For the avoidance of doubt hereā€™s the full set of instructions to try itā€¦
It should not affect any customization you have already done to SketchUp - like installing Extensionsā€¦

  • Log into Windows as your normal user-account - do NOT use a special system administrator account, BUT if your normal user-account has some admin-powers that is OK.

  • Ensure SketchUp is closed.

  • Find your SketchUp installerā€™s exe file - itā€™s usually in your Downloads folder.

  • Select the installerā€™s exe file icon, right-click > context-menu > ā€œRun as administratorā€

  • When prompted choose ā€œRepairā€

  • When it finishes restart SketchUp and see if things have improvedā€¦

You should never install any complex app on a PC by double-clicking its installerā€™s exe fileā€™s icon to ā€œRunā€ it. Even if your normal user-account has some admin powers it is NOT the same thing.
As a result of an improper installation all kinds of unpredictable things can occur, often related to incorrect permission settings, preventing SketchUp [or the user] from saving setting files properly, or reading in files which should be readily accessible.
As I said some days ago, the missing content in SketchUpā€™s dialog is probably related to it being unable to read its own html fileā€¦
Your very recent screenshot shows the content that should appear in the dialog, so the file is OK.

So please ā€œRepairā€ and see if that helpsā€¦

yes i did a repair as an administrator and nothing change with this problem, But i donā€™t have any problem fo doing it again. Iā€™l do it and come back to you.

Unfortunatly itā€™s still de same

In your screen shot Extension Manager is shown with the Internet Explorer icon. Try installing Chrome and using that. Any change?

Please do the followingā€¦
Go to the extension_manager.html file as you did before.
Select its icon, right-click > context-menu > Properties > Security > Edit
Every entry in the list should have at least two of the ā€˜Readā€™ options ticked.
See my example, attached.
What do yours say ?

In mine i donā€™t have this ā€œll APPLICATION PACKAGESā€

but i have in each categorie at leste Read and execute and read

My settings might differ because Iā€™m on Win 10 - are you still on Win 7 ?

Iā€™m running out of ideasā€¦
Anyone else like to chip in ?

Seems like itā€™s getting to the point where an ā€œReinstallā€ might be in orderā€¦
Using the exact same steps as in ā€œRun as administratorā€, once again - but this time choose ā€œUninstallā€.
When that completes, immediately repeat the same steps as in ā€œRun as administratorā€, once again - but this time choose ā€œInstallā€ [if offered].
When that completes reopen SketchUp and see if it helps.

Your Plugins folder should be unaffected ?
But if not try reinstalling the Extensions you want/needā€¦

yes iā€™am on win 7

If i uninstall it, will i lose a licence for a computer?

i did uninstall and reinstall it as administrator and it still de same

do you use explorer or chrome or other? Can that make a difference?

What browser I use is irrelevant.
BUT you might have hit on somethingā€¦
Newer versions of SketchUp ship with their own ā€˜Chromeā€™ browser set up.
This should be used for most of of its own dialogs, [using HTMLdialog Ruby rather than the older WebDialog] and this can also be used by Extensions - but many still use the built-in browsers for backwards compatibilityā€¦
In earlier versions the browser used by all dialogs was the default system browser - in your case PC = Internet Explorer [Safari = for MACs].
If the Extension Manager is still using the older set up, then itā€™s using your Internet Explorer settingsā€¦
So next question, do you have the most current version of Internet Explorer installed - SketchUp expects v11 - Under Win 10 itā€™s v11.615? found from ā€˜About Internet Explorerā€™ - if you have an earlier version, then can you try updating it.
There might be an update option in its ā€˜Aboutā€¦ā€™ dialog, but otherwise look hereā€¦
https://www.microsoft.com/en-gb/download/internet-explorer-11-for-windows-7-details.aspx
Remember to use ā€˜Run as administratorā€™ where appropriateā€¦
Youā€™ll probably need to restart your computer after the updateā€¦

I did but with chrome, i canā€™t download nothing?

You seem to be ā€˜downloadingā€™ OK, but your Extension Managerā€™s dialog is brokenā€¦
That is what we are trying to fix !

Some of this is above my head, but I have 2019 successfully running on a Windows 7 machine. When I installed SU I had Chrome set as my default browser and still is. I have no issue with SU extension manager or 3d Warehouse for that matter.

I just tried Internet Explorer as my default browser and the Extension manager window still opens fine. So things are working alright for me here.