Upgrading Drupal

We are trying (for the second time) to upgrade D6 to D7 for a site with a 40GB database.

Everything *seems* to have upgraded properly except the Taxonomy.

On the D6 site the
- term_node table has about 71M rows and is 8.2 GB.
- term_data table has about 2M rows and is 238 MB.

After doing the upgrade and getting this error:

Update #7005
Failed: DatabaseSchemaObjectExistsException: Table taxonomy_update_7005 already exists. in DatabaseSchema->createTable() (line 660 of ... /includes/database/schema.inc).

I just updated from 8.05 to 8.10, but when I run update.php, the Verify Requirements tab responds with
Unresolved dependency System (Version <8.1 required)
Drupal Upgrade requires this module and version. Currently using System version 8.1.0

Well of course I am using 8.1, because I just installed those files, why is it saying I need an older version?

Looking for any help.

When i run update.php i receive this error:

An AJAX HTTP error occurred.
HTTP Result Code: 500
Debugging information follows.
Path: /update.php/start?id=88&op=do_nojs&op=do
StatusText: Internal Server Error
ResponseText:

error_log:

Hi

We are looking to migrate from 6 to 7, and would like to get into contact with someone that has the experience to perform this.

We use our website as a storefront and need to make sure you know how to manage SSL certificates, severs, shipping mod's.

Looking for someone to permanently manage the website.

Please contact me at

Ty
candoprinting@yahoo.com
602-233-1111x59
U.S.

I'm in week 9 of trying to get a Drupal 6 site upgraded to Drupal 8. After lots of frustration (I'm kind of thinking that even though the site is several hundred pages, it would be easier and faster to start entering data manually - and I know it would be easier to just build a site from scratch the the proper tools to manage the content that needs to be managed, but the client has a requirement to use Drupal), I have finally gotten it to a point where it appears that the drush migrate-upgrade script will run.

I've searched and there are many topics about upgrading modules, etc. with composer and that works for me. However the posts I've found on updating core with composer are outdated with a composer.json file that does not match what you get with 8.0.5 and/or include a bunch of post script processing.

I installed drupal clean with

$ composer create-project drupal/drupal /home/mydir/public_html 8.0.5

This gave me a composer.json with this as the entry for drupal core.

"replace": {
"drupal/core": "~8.0"
},