"Insufficient storage - The device does not have enough space to download…" error only when downloading a language pack in Swiftkey

Question

I'm always getting this error message when trying to download another language pack in SwiftKey:

Insufficient storage - The device does not have enough space to download [language]. Consider deleting apps or content that you no longer need and try again. ^{[Screenshot 1]}

However, I have 3.33 GB of available space in internal storage ^{[Screenshot 2]} and 3.68 GB in the SD card ^{[Screenshot 3]}. This error never occurs in any other app, even those installed after SwiftKey. And it only happens when installing another language pack within SwiftKey. It does not happen when reinstalling SwiftKey or when changing the theme in SwiftKey. I've already tried:

• Uninstalling even more apps
• Moving apps to SD card (for those apps that allow moving to SD card)
• Clearing the cache and data of SwiftKey and retrying the language pack download
• Uninstalling and reinstalling SwiftKey (also tried clearing cache and data before uninstalling)
• Running the SD Maid app's AppControl and CorpseFinder cleaning modes after uninstalling
• Searching for files with 'SwiftKey' in their names in SD Maid to ensure that no SwiftKey files are left behind after uninstalling SwiftKey. Also tried searching with the Amaze file manager app (root mode). No files are found in both searching methods.
• Used the Delete old messages app to delete many of my old messages

Solutions suggested by answers in other related posts:

• Languages wont download [SwiftKey forums]
  • Tapped on 'Update languages'' in the language download menu and after that tried downloading the language pack again
  • Attempted deleting the 'languagePacks.json' file at /sdcard/Android/data/com.touchtype.swiftkey/files/. However, there is no 'languagePacks.json' file under the 'files' directory.
• Why am I constantly running out of space on my Galaxy S2?
  • Dialling *#9900# to attempt to delete dumpstate/logcat but I'm getting a "Connection problem or invalid MMI code" error message
  • Deleting contents of /data/logs but there is no 'logs' folder under 'data'. There is a 'log' (no 's') folder, though, and I've deleted all of it contents.
• Install/Update Apps gives “Insufficient Storage Available” error, although I already cleared the cache and other data
  • Deleting contents of /data/app-lib/APP-PATH [that has this error]/lib while SwiftKey is installed, however the 'lib' folder does not exist.
  • Deleting /data/app-lib/APP-PATH [that has this error]
  • Deleting /data/app-lib/APP-PATH after uninstalling, however this path does not exist for SwiftKey after it has been uninstalled (it seems that an uninstall clears it properly)
• Titanium Backup “insufficient free storage space” error
  • Unticked 'Mount namespace separation' setting in SuperSU
• How to empty (clear) the logcat buffer in Android
  • Tried the adb logcat -c command

I've restarted the phone after doing the above-mentioned attempts, but they haven't fixed the issue. The error message still appears when I attempt to download another language.

Is there anything else I could try to resolve the issue?

Details:
Device: Huawei Honor 3C H30-U10
Android version: 4.2.2 Jelly Bean
The device is rooted. Superuser management app: SuperSU.

Answer 1

Turns out this was a bug with SwiftKey and was fixed in version 6.3.6:

Fixed: ‘Insufficient storage’ error message will not appear when downloading languages

Before that version, I did a workaround by restoring a backup of SwiftKey's data using Titanium Backup (requires root) from another device with SwiftKey and the language pack already downloaded and installed. This will however, keep the settings and logged-in user data of the source device, so you'll to log-out the existing user and edit the settings after you have restored the SwiftKey data.