[solved] "Use SEO URLs"-Yes, get 404 and no index.php

Fresh v1.5.2.1, My host says "The Apache module "mod-rewrite" is currently installed and enabled on all of our servers by default". I changed at /public_html/store/ the file name to .htaccess (and ".htaccess." , I am not sure which is correct). I set in admin/store/settings/server to Yes for "Use SEO Urls".
The result is good URLs for products and categories, but only the "home" page shows up/loads as mysite/com/store/. The other pages give:
Not Found
The requested URL /store/VX18-home-gym was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

I am clearing browsing data after changes. Some times I get the similar 404 not found result, but it says it can't find "URL/index.php on this server" instead, which is also in /public_html/store/ (same folder as the .htaccess file) (this happens if I name the file ".htaccess" ).

What should I try next. None of the 6 commented commands in the htaccess file seem like they will help if I uncomment them.

Thank you

change rewrite base from / to /shop/ that will solve your problem

Thank you for the reply. I went to the htaccess file at /public_html/store/ (Itried both .htaccess. and .htaccess as file names) and I got the same result (404 not found) after I changed this section to:

# SEO URL Settings
RewriteEngine On
# If your opencart installation does not run on the main web folder make sure you folder it does run in ie. / becomes /shop/

RewriteBase /shop/
RewriteRule ^sitemap.xml$ index.php?route=feed/google_sitemap [L]
RewriteRule ^googlebase.xml$ index.php?route=feed/google_base [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !.*\.(ico|gif|jpg|jpeg|png|js|css)
RewriteRule ^([^?]*) index.php?_route_=$1 [L,QSA]

This is the full result:
Not Found
The requested URL /store/home-gyms was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

I cleared the web browsing/cache/cookies data. I thank you for your reply, but I haven't quite got it yet. What do you think?
Thank you.

Oops. I fixed my problem.
I changed to "store" instead of "shop". That was dumb.
It works now with ".htaccess" as the file name.
Thank you.

Hi Sir I am also getting the same problem home page is loading fine but rest of pages gives the same error

"Not Found
The requested URL /9-axis-magnetic-acceleration-gyro-module-GY80 was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request."

My .htaccess file is
-------------------------------------------------------------------------------------------------------------------------
# 1.To use URL Alias you need to be running apache with mod_rewrite enabled.

# 2. In your opencart directory rename htaccess.txt to .htaccess.

# For any support issues please visit: http://www.opencart.com

Options +FollowSymlinks

# Prevent Directoy listing
Options -Indexes

# Prevent Direct Access to files
<FilesMatch "\.(tpl|ini|log)">
Order deny,allow
Deny from all
</FilesMatch>

# SEO URL Settings
RewriteEngine On
# If your opencart installation does not run on the main web folder make sure you folder it does run in ie. / becomes /shop/

RewriteBase /
RewriteRule ^sitemap.xml$ index.php?route=feed/google_sitemap [L]
RewriteRule ^googlebase.xml$ index.php?route=feed/google_base [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !.*\.(ico|gif|jpg|jpeg|png|js|css)
RewriteRule ^([^?]*) index.php?_route_=$1 [L,QSA]

### Additional Settings that may need to be enabled for some servers
### Uncomment the commands by removing the # sign in front of it.
### If you get an "Internal Server Error 500" after enabling any of the following settings, restore the # as this means your host doesn't allow that.

# 1. If your cart only allows you to add one item at a time, it is possible register_globals is on. This may work to disable it:
# php_flag register_globals off

# 2. If your cart has magic quotes enabled, This may work to disable it:
# php_flag magic_quotes_gpc Off

# 3. Set max upload file size. Most hosts will limit this and not allow it to be overridden but you can try
# php_value upload_max_filesize 999M

# 4. set max post size. uncomment this line if you have a lot of product options or are getting errors where forms are not saving all fields
# php_value post_max_size 999M

# 5. set max time script can take. uncomment this line if you have a lot of product options or are getting errors where forms are not saving all fields
# php_value max_execution_time 200

# 6. set max time for input to be recieved. Uncomment this line if you have a lot of product options or are getting errors where forms are not saving all fields
# php_value max_input_time 200

# 7. disable open_basedir limitations
# php_admin_value open_basedir none
--------------------------------------------------------------------------------------------------------------------------
I did the modification as you suggested in above posts but still i am getting same error
I am sharing the whole path of my files on server, It will help you to find where i am getting wrong
screen.
Thanking you so much, I hope you will reply soon

you are missing the dot at the front of the file name. It needs to be .htaccess and not htaccess.

Thank you so much sir

same, i got the problem too. I was editting my website with capthca from google and SEO BUT I never edit entire website directly from File Manager!, i used the automation whose given by the google. And when i access my website i got this error. But when i open my file manager, i found that my .htaccess file was renamed with .htaccess.txt. And now my website back to normal. Thanks