diff --git a/app/detekt_baseline.xml b/app/detekt_baseline.xml
index e8547da19..a2dff3391 100644
--- a/app/detekt_baseline.xml
+++ b/app/detekt_baseline.xml
@@ -7,12 +7,12 @@
     <ID>EmptyFunctionBlock:ZimHostActivity.kt$ZimHostActivity.&lt;no name provided&gt;${}</ID>
     <ID>ForbiddenComment:KiwixMainActivity.kt$KiwixMainActivity$// TODO: Show to user</ID>
     <ID>LongParameterList:ZimManageViewModel.kt$ZimManageViewModel$( booksOnFileSystem: List&lt;BookOnDisk&gt;, activeDownloads: List&lt;DownloadModel&gt;, allLanguages: List&lt;Language&gt;, libraryNetworkEntity: LibraryNetworkEntity, filter: String, fileSystemState: FileSystemState )</ID>
-    <ID>MagicNumber:LibraryFragment.kt$LibraryFragment$1024f</ID>
     <ID>MagicNumber:LibraryListItem.kt$LibraryListItem.LibraryDownloadItem$1000L</ID>
     <ID>MagicNumber:ShareFiles.kt$ShareFiles$24</ID>
     <ID>MagicNumber:ZimManageViewModel.kt$ZimManageViewModel$5</ID>
     <ID>MagicNumber:ZimManageViewModel.kt$ZimManageViewModel$500</ID>
     <ID>MagicNumber:ZimManageViewModel.kt$ZimManageViewModel$60</ID>
+    <ID>PackageNaming:AvailableSpaceCalculator.kt$package org.kiwix.kiwixmobile.zim_manager.library_view</ID>
     <ID>PackageNaming:ConnectivityBroadcastReceiver.kt$package org.kiwix.kiwixmobile.zim_manager</ID>
     <ID>PackageNaming:DefaultLanguageProvider.kt$package org.kiwix.kiwixmobile.zim_manager</ID>
     <ID>PackageNaming:DeleteFiles.kt$package org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects</ID>
@@ -42,7 +42,6 @@
     <ID>PackageNaming:ZimManageViewModel.kt$package org.kiwix.kiwixmobile.zim_manager</ID>
     <ID>ReturnCount:Fat32Checker.kt$Fat32Checker$private fun canCreate4GbFile(storage: String): Boolean</ID>
     <ID>ReturnCount:LanguageActivity.kt$LanguageActivity$override fun onOptionsItemSelected(item: MenuItem): Boolean</ID>
-    <ID>ReturnCount:LibraryFragment.kt$LibraryFragment$private fun onBookItemClick(item: BookItem)</ID>
     <ID>TooGenericExceptionCaught:FileWritingFileSystemChecker.kt$FileWritingFileSystemChecker$e: Exception</ID>
     <ID>TooGenericExceptionCaught:KiwixMainActivity.kt$KiwixMainActivity$e: Exception</ID>
     <ID>TooGenericExceptionThrown:ActivityExtensions.kt$throw RuntimeException( """ applicationContext is ${applicationContext::class.java.simpleName} application is ${application::class.java.simpleName} """.trimIndent() )</ID>
diff --git a/app/src/main/java/org/kiwix/kiwixmobile/settings/KiwixPrefsFragment.kt b/app/src/main/java/org/kiwix/kiwixmobile/settings/KiwixPrefsFragment.kt
index dcdcdcb0a..f745636d2 100644
--- a/app/src/main/java/org/kiwix/kiwixmobile/settings/KiwixPrefsFragment.kt
+++ b/app/src/main/java/org/kiwix/kiwixmobile/settings/KiwixPrefsFragment.kt
@@ -23,7 +23,6 @@ import android.os.Environment
 import org.kiwix.kiwixmobile.core.settings.CorePrefsFragment
 import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil.PREF_LANG
 import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil.PREF_STORAGE
-import java.io.File
 
 class KiwixPrefsFragment : CorePrefsFragment() {
   override fun onCreate(savedInstanceState: Bundle?) {
@@ -37,7 +36,6 @@ class KiwixPrefsFragment : CorePrefsFragment() {
     } else {
       findPreference(PREF_STORAGE).title = sharedPreferenceUtil.getPrefStorageTitle("External")
     }
-    findPreference(PREF_STORAGE).summary =
-      storageCalculator.calculateAvailableSpace(File(sharedPreferenceUtil.prefStorage))
+    findPreference(PREF_STORAGE).summary = storageCalculator.calculateAvailableSpace()
   }
 }
diff --git a/app/src/main/java/org/kiwix/kiwixmobile/zim_manager/library_view/AvailableSpaceCalculator.kt b/app/src/main/java/org/kiwix/kiwixmobile/zim_manager/library_view/AvailableSpaceCalculator.kt
new file mode 100644
index 000000000..b0a5de365
--- /dev/null
+++ b/app/src/main/java/org/kiwix/kiwixmobile/zim_manager/library_view/AvailableSpaceCalculator.kt
@@ -0,0 +1,53 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2020 Kiwix <android.kiwix.org>
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.zim_manager.library_view
+
+import eu.mhutti1.utils.storage.Bytes
+import eu.mhutti1.utils.storage.Kb
+import io.reactivex.android.schedulers.AndroidSchedulers
+import io.reactivex.schedulers.Schedulers
+import org.kiwix.kiwixmobile.core.dao.FetchDownloadDao
+import org.kiwix.kiwixmobile.core.downloader.model.DownloadModel
+import org.kiwix.kiwixmobile.core.settings.StorageCalculator
+import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryListItem
+import javax.inject.Inject
+
+class AvailableSpaceCalculator @Inject constructor(
+  private val downloadDao: FetchDownloadDao,
+  private val storageCalculator: StorageCalculator
+) {
+  fun hasAvailableSpaceFor(
+    bookItem: LibraryListItem.BookItem,
+    successAction: (LibraryListItem.BookItem) -> Unit,
+    failureAction: (String) -> Unit
+  ) {
+    downloadDao.allDownloads()
+      .map { it.map(DownloadModel::bytesRemaining).sum() }
+      .map { bytesToBeDownloaded -> storageCalculator.availableBytes() - bytesToBeDownloaded }
+      .subscribeOn(Schedulers.io())
+      .observeOn(AndroidSchedulers.mainThread())
+      .subscribe { trueAvailableBytes ->
+        if (bookItem.book.size.toLong() * Kb < trueAvailableBytes) {
+          successAction.invoke(bookItem)
+        } else {
+          failureAction.invoke(Bytes(trueAvailableBytes).humanReadable)
+        }
+      }
+  }
+}
diff --git a/app/src/main/java/org/kiwix/kiwixmobile/zim_manager/library_view/LibraryFragment.kt b/app/src/main/java/org/kiwix/kiwixmobile/zim_manager/library_view/LibraryFragment.kt
index a47f72845..6707954ef 100644
--- a/app/src/main/java/org/kiwix/kiwixmobile/zim_manager/library_view/LibraryFragment.kt
+++ b/app/src/main/java/org/kiwix/kiwixmobile/zim_manager/library_view/LibraryFragment.kt
@@ -42,7 +42,6 @@ import org.kiwix.kiwixmobile.core.downloader.Downloader
 import org.kiwix.kiwixmobile.core.entity.LibraryNetworkEntity.Book
 import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.viewModel
 import org.kiwix.kiwixmobile.core.extensions.snack
-import org.kiwix.kiwixmobile.core.settings.StorageCalculator
 import org.kiwix.kiwixmobile.core.utils.BookUtils
 import org.kiwix.kiwixmobile.core.utils.DialogShower
 import org.kiwix.kiwixmobile.core.utils.KiwixDialog.YesNoDialog.StopDownload
@@ -60,7 +59,6 @@ import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryDelegate.Di
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryDelegate.DownloadDelegate
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryListItem
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryListItem.BookItem
-import java.io.File
 import javax.inject.Inject
 
 class LibraryFragment : BaseFragment() {
@@ -71,7 +69,7 @@ class LibraryFragment : BaseFragment() {
   @Inject lateinit var dialogShower: DialogShower
   @Inject lateinit var viewModelFactory: ViewModelProvider.Factory
   @Inject lateinit var bookUtils: BookUtils
-  @Inject lateinit var storageCalculator: StorageCalculator
+  @Inject lateinit var availableSpaceCalculator: AvailableSpaceCalculator
 
   private val zimManageViewModel by lazy {
     activity!!.viewModel<ZimManageViewModel>(viewModelFactory)
@@ -87,9 +85,6 @@ class LibraryFragment : BaseFragment() {
     )
   }
 
-  private val spaceAvailable: Long
-    get() = storageCalculator.availableBytes(File(sharedPreferenceUtil.prefStorage))
-
   private val noWifiWithWifiOnlyPreferenceSet
     get() = sharedPreferenceUtil.prefWifiOnly && !NetworkUtils.isWiFi(context!!)
 
@@ -192,16 +187,6 @@ class LibraryFragment : BaseFragment() {
 
   private fun onBookItemClick(item: BookItem) {
     when {
-      notEnoughSpaceAvailable(item) -> {
-        libraryList.snack(
-          getString(R.string.download_no_space) +
-            "\n" + getString(R.string.space_available) + " " +
-            storageCalculator.calculateAvailableSpace(File(sharedPreferenceUtil.prefStorage)),
-          R.string.download_change_storage,
-          ::showStorageSelectDialog
-        )
-        return
-      }
       isNotConnected -> {
         noInternetSnackbar()
         return
@@ -213,13 +198,20 @@ class LibraryFragment : BaseFragment() {
         })
         return
       }
-      else -> downloadFile(item.book)
+      else -> availableSpaceCalculator.hasAvailableSpaceFor(item,
+        { downloadFile(item.book) },
+        {
+          libraryList.snack(
+            getString(R.string.download_no_space) +
+              "\n" + getString(R.string.space_available) + " " +
+              it,
+            R.string.download_change_storage,
+            ::showStorageSelectDialog
+          )
+        })
     }
   }
 
-  private fun notEnoughSpaceAvailable(item: BookItem) =
-    spaceAvailable < item.book.size.toLong() * 1024f
-
   private fun showStorageSelectDialog() = StorageSelectDialog()
     .apply {
       onSelectAction = ::storeDeviceInPreferences
diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/dao/FetchDownloadDao.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/dao/FetchDownloadDao.kt
index e3f9dcf3d..2a6045e80 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/dao/FetchDownloadDao.kt
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/dao/FetchDownloadDao.kt
@@ -23,6 +23,7 @@ import io.objectbox.Box
 import io.objectbox.kotlin.equal
 import io.objectbox.kotlin.query
 import io.reactivex.Flowable
+import io.reactivex.Single
 import org.kiwix.kiwixmobile.core.dao.entities.FetchDownloadEntity
 import org.kiwix.kiwixmobile.core.dao.entities.FetchDownloadEntity_
 import org.kiwix.kiwixmobile.core.downloader.DownloadRequester
@@ -43,6 +44,8 @@ class FetchDownloadDao @Inject constructor(
       .doOnNext(::moveCompletedToBooksOnDiskDao)
       .map { it.map(::DownloadModel) }
 
+  fun allDownloads() = Single.fromCallable { box.all.map(::DownloadModel) }
+
   private fun moveCompletedToBooksOnDiskDao(downloadEntities: List<FetchDownloadEntity>) {
     downloadEntities.filter { it.status == COMPLETED }.takeIf { it.isNotEmpty() }?.let {
       box.store.callInTx {
diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/di/modules/DownloaderModule.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/di/modules/DownloaderModule.kt
index 32d83660b..6b608ce53 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/di/modules/DownloaderModule.kt
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/di/modules/DownloaderModule.kt
@@ -73,13 +73,19 @@ object DownloaderModule {
       enableLogging(BuildConfig.DEBUG)
       enableRetryOnNetworkGain(true)
       setHttpDownloader(okHttpDownloader)
+      preAllocateFileOnCreation(false)
       setNotificationManager(fetchNotificationManager)
     }.build().also(Impl::setDefaultInstanceConfiguration)
 
   @JvmStatic
   @Provides
   @Singleton
-  fun provideOkHttpDownloader() = OkHttpDownloader(OkHttpClient.Builder().build())
+  fun provideOkHttpDownloader() = OkHttpDownloader(
+    OkHttpClient.Builder()
+      .followRedirects(true)
+      .followSslRedirects(true)
+      .build()
+  )
 
   @JvmStatic
   @Provides
diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/model/DownloadModel.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/model/DownloadModel.kt
index 6c1c518e3..a1261029a 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/model/DownloadModel.kt
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/downloader/model/DownloadModel.kt
@@ -35,6 +35,7 @@ data class DownloadModel(
   val progress: Int,
   val book: Book
 ) {
+  val bytesRemaining: Long by lazy { totalSizeOfDownload - bytesDownloaded }
   val fileNameFromUrl: String by lazy { StorageUtils.getFileNameFromUrl(book.url) }
 
   constructor(downloadEntity: FetchDownloadEntity) : this(
diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/settings/StorageCalculator.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/settings/StorageCalculator.kt
index 4f9e441fc..cee87f469 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/settings/StorageCalculator.kt
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/settings/StorageCalculator.kt
@@ -19,18 +19,21 @@
 package org.kiwix.kiwixmobile.core.settings
 
 import eu.mhutti1.utils.storage.Bytes
+import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
 import java.io.File
 import javax.inject.Inject
 
-class StorageCalculator @Inject constructor() {
+class StorageCalculator @Inject constructor(
+  private val sharedPreferenceUtil: SharedPreferenceUtil
+) {
 
-  fun calculateAvailableSpace(file: File): String =
+  fun calculateAvailableSpace(file: File = File(sharedPreferenceUtil.prefStorage)): String =
     Bytes(availableBytes(file)).humanReadable
 
-  fun calculateTotalSpace(file: File): String =
+  fun calculateTotalSpace(file: File = File(sharedPreferenceUtil.prefStorage)): String =
     Bytes(totalBytes(file)).humanReadable
 
-  fun availableBytes(file: File) =
+  fun availableBytes(file: File = File(sharedPreferenceUtil.prefStorage)) =
     if (file.exists()) file.freeSpace
     else 0L
 
diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/utils/SharedPreferenceUtil.java b/core/src/main/java/org/kiwix/kiwixmobile/core/utils/SharedPreferenceUtil.java
index b041e5d87..7a34f1111 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/utils/SharedPreferenceUtil.java
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/utils/SharedPreferenceUtil.java
@@ -110,17 +110,24 @@ public class SharedPreferenceUtil {
   }
 
   public String getPrefStorage() {
-    String storage = sharedPreferences.getString(PREF_STORAGE, null);
+    final String storage = sharedPreferences.getString(PREF_STORAGE, null);
     if (storage == null) {
-      final File externalFilesDir =
-        ContextCompat.getExternalFilesDirs(CoreApp.getInstance(), null)[0];
-      storage = externalFilesDir != null ? externalFilesDir.getPath()
-        : CoreApp.getInstance().getFilesDir().getPath(); // workaround for emulators
-      putPrefStorage(storage);
+      final String defaultStorage = defaultStorage();
+      putPrefStorage(defaultStorage);
+      return defaultStorage;
+    } else if (!new File(storage).exists()) {
+      return defaultStorage();
     }
     return storage;
   }
 
+  private String defaultStorage() {
+    final File externalFilesDir =
+      ContextCompat.getExternalFilesDirs(CoreApp.getInstance(), null)[0];
+    return externalFilesDir != null ? externalFilesDir.getPath()
+      : CoreApp.getInstance().getFilesDir().getPath(); // workaround for emulators
+  }
+
   public String getPrefStorageTitle(String defaultTitle) {
     return sharedPreferences.getString(PREF_STORAGE_TITLE, defaultTitle);
   }
diff --git a/core/src/test/java/org/kiwix/kiwixmobile/core/settings/StorageCalculatorTest.kt b/core/src/test/java/org/kiwix/kiwixmobile/core/settings/StorageCalculatorTest.kt
index 245ad967a..dadced942 100644
--- a/core/src/test/java/org/kiwix/kiwixmobile/core/settings/StorageCalculatorTest.kt
+++ b/core/src/test/java/org/kiwix/kiwixmobile/core/settings/StorageCalculatorTest.kt
@@ -26,7 +26,7 @@ import java.io.File
 
 internal class StorageCalculatorTest {
 
-  private val storageCalculator = StorageCalculator()
+  private val storageCalculator = StorageCalculator(mockk())
   private val file: File = mockk()
 
   @Test