I have installed the new files of Osclass 3.8.1. When I log in as admin and try to connect the osclass market I get the updrade page as shown in snapshots. When I click updrade now its loading and taking long time without upgrading anything. What is the issue and how to resolve it?

Osclass 3.8 is not stable anymore due to market connection that is shut down.
Use osclass 4.1.
https://osclass-classifieds.com

Ok I will try that.

Good, let me know

I have uploaded the osclass 4.1.1 files and tried upgrade now. But still the upgrade is not completing.

There was bug in old upgrade process that it did nit show complete message.
Basically everything should be completed in few seconds, no mire than 5 minutes.
You may slso check your browser console as well as error log.
If upgrade was made ok and you refresh page in several minutes, iit should be completed.
But if upgrade was made just partially, some steps may not be repeated and you could get errors that will block upgrade process.
Also set chmod to all your folders recursively to 755, just to be sure.

I changed the chmod of directory files and folder to 755 recursively. And on clicking dashboard the Upgrade Now button page comes. I clicked the upgrade now, after some times the page redirected to my main directory platform showing Error 404 Page and on trying mainsite.com/classifieds/oc-admin the page redirects to Error 404 Page. I cannot login now as admin. I check the classified website on incognito windows and the color of the header and logo has changed. What can I do now?

@Sinto001
That sounds like your osclass installation may be corrupted.
Anyway update has no effect on passwords (front or back) so you must be able to login using same password.
However, if you have some php errors (or database errors) on background, this may cause problems with login.

In that case you should enable error log (for php as well as database) and look what are you getting.

I cannot open the classified/oc-admin page to log in as admin. The logging url redirects to Error 404 Page. Where I should enable the error log files in main root directory or in the directory where osclass is installed?

You may find all details at documentation.
You should be able to open oc-admin anyway, try to reupload installation files and clean htaccess file.

I forgot to disable permalinks I cannot disable it now everytime I go to permalinks I get the upgrade now button page.

You can remove htaccess file and disable permalinks in t_preference table on database

I asked my hosting provider to reinstate my classified site to old site. They did it and then I disabled the permalinks and uploaded the new osclass-v4.1.1 files. I could login as admin using my opera browser with VPN enabled could not do so in chrome browser. I got the page

Tools
Upgrade
You have uploaded a new version of Osclass, you need to upgrade Osclass for it to work correctly.

I clicked upgrade now button. But after waiting for more that 30 minutes the page remain like

Tools
Upgrade
 Upgrading your Osclass installation (this could take a while):

I looked at frontend the header color and logo have changed. Also login as user cannot upload any images. Google Maps not working correctly as it was previously also.

How can all this be fixed, can I hire a support person to correct this?

This does not sound ok but I have no idea how to help you. It could be hostingvrelated as well.
You may send your request to [email protected]

Please help the upgrade is not completing and existing site has no option to upload images for the ad listing that user makes.