Why does my play store downloads get stuck at around 90% but never finish?

Hi, Thanks for posting in Google help forums,

Check Device Certification status,

For certified Device,

Deactivate Find my Device temporarily,

Clear Data in Google Play store,

Uninstall updates in Google Play services,

Next,Update Google Play services,

Methods,

Leave the Device for some time 5 / 10 minutes and allow Play services update Automatically,

OR,

Pull down the notification bar and select “ Update Google Play services “ prompt,

OR,

Open the link and update  Google play services,

After finishing,

Select Account for  Backup Data,

Activate Find my Device,

Restart Device.

Reset Device to Factory Default settings and Set-up Device as a New Device,

Next,

Plug your Device in Charger,

Remove SD / Memory card if mounted,

Check Sync settings,

Check Settings in Google Drive,

Next,

Save  your Passwords /  Data / Files / Photos / Videos  / Contacts / X/ X/ into Google Account,

Save your Installed Non  Default Third party Apps links in Gmail or Google Drive 

Next Save your personal dictionary into Google Drive,

Before Reset,

Open Google Drive and make a new folder for dictionary,

Launch Gboard in any app and follow the instructions and Save dictionary,

To prevent wrong Settings and unwanted Data   from backing up,

Delete Back-up in Google drive,

Clear data for Google Play services

Next, Settings > Google>Select Backup off,

Next,

Open the link,

Switch between accounts and find  Default Account for this Device,

First of all remove Non default Accounts,

Finally remove Default Account,

Next,

Reset Device to Factory default Settings,

While Set-up Device  Select Set-up as New Device,

Upgraded Android version will not be degraded,

All Data successfully synchronised from the last time  with Google account such as Google contacts, Google photos, Google Drive file etc and third party app data synchronised with Google drive will be restored, other data stored in device internal memory such as,

Call history , SMS, MMS , Offline Google maps,Photos in Default Gallery etc will be deleted permanently,

Added credentials, AppLock, screen lock, Fingerprint, will be erased,

After set-up you can find your previous Apps here,

For Restore personal dictionary,

After Reset,

Launch Gboard in any app,

Select settings and follow the instructions,

After finishing set-up,

Leave the Device for few minutes to Update Google Play Store and Google Play Services automatically,

Next,

Select Automatically Sync Data On and Check successful syncing in Apps,

Start initially with System Default Apps only,

Keep running Device and check for any issues, 

Before removing Accounts ,Make sure you will be able to sign back with 2 step verification,

Or,

Generate 8 digit Backup codes and keep these codes out of Device and Account to Sign back after Reset ( important),